I voted that I really don't care.
I understand that a customer has no legal obligation to abide by these searches. On the other hand, if me shopping at a store that I like, such as Best Buy, required that I be a part of an agreement where my bag is inspected upon leaving, I would go along with the agreement. In the name of preventing theft, and consequently keeping prices down, so be it.
I'm sure people have seen signs at businesses that say something to the effect of "This establishment reserves the right to refuse service to anyone for any reason." Why doesn't a place like Best Buy have the right to refuse service to people who refuse to comply with bag searches? Or is that completely illegal? I've never signed anything at these business that have a type of sign like I mentioned, either. And I would personally find it adequate if this information was plainly visible at the store entrance, as opposed to me having to sign something.
Well, whatever. I don't really care all that much.