I believe game theory, and specifically, the theory of The Prisoner's Dilemma, can explain why.
In case you don't know what game theory is, I'll try to explain. Taken straight from wikipedia: Game theory is the study of strategic decision making. In other words, it's just the study of why people do what they decide to do.
The Prisoner's Dilemma is a specific game devised by a couple of American mathematicians in the 1950s to explain why people will behave they do. The Prisoner's Dilemma is presented as follows:
Two members of a criminal gang are arrested and imprisoned. Each prisoner is in solitary confinement with no means of speaking to or exchanging messages with the other. The police admit they don't have enough evidence to convict the pair on the principal charge. They plan to sentence both to a year in prison on a lesser charge. Simultaneously, the police offer each prisoner a Faustian bargain. If he testifies against his partner, he will go free while the partner will get three years in prison on the main charge. Oh, yes, there is a catch ... If both prisoners testify against each other, both will be sentenced to two years in jail.
Thus, each prisoner has an incentive to rat out the other prisoner. If one prisoner rats out the other and the other prisoner admits to the crime, then the rat gets out of jail and the admitting prisoner goes to jail. If both prisoners don't rat each other out, they don't go to jail and get off scot-free. If both prisoners rat each other out then they both go to jail. A similar Prisoner's Dilemma chart is shown below. Although the amount of jail time is different, the dilemma is just the same: mutual cooperation is best, mutual betrayal is bad, a unilateral betrayal is really bad for the non-confessor but really good for the confessor.
Clearly, it is in both prisoner's best interests to not rat each other out. If you were a prisoner, what would you do? Most people would probably rat out the other prisoner on the hopes that the other prisoner won't rat you out. The result would be that you would get off scot-free and the other prisoner would go to jail. You win. Can you blame a person for thinking this way and wanting this outcome? Human beings are hardwired for self-preservation. You want to take care of yourself before you take care of others. You'd rather have yourself benefit rather than have someone else benefit.
The Prisoner's Dilemma is actually a very similar game to the show The Bachelor Pad. In case you don't watch that show (I don't but I know the premise of the show) I'll explain. A large group of bachelors and bachelorettes are put on a show to win a million dollars. They must pair up to compete against each other and accomplish tasks. Each week some of them are eliminated. The goal is to be the last bachelor and last bachelorette remaining. At the very end of the show the bachelor and the bachelorette decide whether to they will split the winnings or keep the winnings for themselves. If they both decide to split the money, then they'll split the money. If one decides to split the money and the other decides to keep the money for themselves, the one who decided to keep the money for themselves will get all the money and the one who decided to split the money will get nothing. (Ouch!) If they both decide to keep the money for themselves then neither of them gets anything. (More ouch!) Clearly, there is incentive for both parties to split the money. Cooperation will lead to both of them getting half of the money. But greed and mistrust of the other person will lead to one person choosing to keep the money. The decision faced by the final two contestants is the quintessential Prisoner's Dilemma, just in another form.
Pack searching is also a prisoner's dilemma.
Imagine there are only two card collectors in one city. Each one can either choose to pack search or not to pack search. If both of them decide not to pack search, then they can go about buying packs of cards without fear of it being searched and both of them will get hits from retail! Buying sports cards will be a pleasant and fun experience for them and any other card collectors who also may come along. If both of them decide to pack search then they'll end up splitting all the retail hits between the two of them. Buying sports cards will be very competitive for them, and very unpleasant for any other card collectors who may come along because they won't get any hits. On the other hand, if only one of them decides to pack search and the other decides not to pack search, then the pack searcher will get all the retail hits and the non-pack searcher won't get any retail hits. This too, is The Prisoner's Dilemma.
I believe game theory, and specifically the Prisoner's Dilemma is a perfect way to explain why card collectors, especially pack searchers, will behave the way they do. Everyone wants the best for themselves. Pack searchers, and card collectors in general, want the best cards for themselves. In the ideal scenario, if everyone didn't pack search then everyone would benefit. But that can only happen if everyone demonstrates self-restraint, resistance of greed, resistance of the desire to pack search retail products to find the best cards for yourself, and trust in others to not pack search when it can be so easily done. Can you do all those things? If you can't, I don't blame you. I think it's just human nature to want the best for yourself, even if that means others get the shorter end of the stick.
In the prisoner's dilemma, most of us will choose to rat the other person out. We will do this out of our concern for self-preservation -- getting the best outcome for our self. When it comes to pack searching, I think a lot of us will choose to pack search. While it is not a situation of self-preservation, you still want the best outcome for yourself when you buy a pack of cards -- and that means pack searching. Do you really trust all the other collectors out there to not pack search? I don't. If you feel the same way, I don't blame you. I think it's only human nature to want the best for yourself and that humans will act accordingly to fulfill that goal. That means people will pack search. That means other people will pack search in response to those original pack searchers because the original pack searchers can't be trusted to not pack search. The result is a cumulative build-up of more and more people pack searching. Everyone, non-pack searchers and pack searchers alike, will suffer from this desire to find the best outcome for yourself and this mistrust of others to not pack search. It is unfortunate, but it is how it is. It is human nature. In the Prisoner's Dilemma, this is the equivalent of both prisoners confessing.
Pack searching is a Prisoner's Dilemma, and it is one that we are all likely to lose.