Hmm; what you're saying is true, so I think I phrased my statement a bit wrong. In general, yes, people do want to help. But your bank just isn't in the business of knowing what's in its safe-deposit boxes, just like Tarsnap isn't in the business of knowing what's on its servers.
The whole business model of a safe-deposit box relies on other people not being able to get into them without the owner's consent—so if anyone, including the bank itself, took a peek in there, that would instantly lose them all the trust they had ever accrued as a safe-deposit-box provider—and thus a lot of money. They have much more of an incentive to keep your data private than they have an incentive to help those who want it, because keeping your data private is what keeps them in business. That's the meaning I was going for.
The whole business model of a safe-deposit box relies on other people not being able to get into them without the owner's consent—so if anyone, including the bank itself, took a peek in there, that would instantly lose them all the trust they had ever accrued as a safe-deposit-box provider—and thus a lot of money. They have much more of an incentive to keep your data private than they have an incentive to help those who want it, because keeping your data private is what keeps them in business. That's the meaning I was going for.