I'll note that like many of the comments on HN and elsewhere that comment on what something is like in the US that the true answer depends on where you are within the US. With the issue it is going to vary tremendously based on which store you are in. I believe in my state at least you also have to leave the store before any law is broken, although such laws are set at the state level and so there may be exceptions.

I think the law is probably reasonable in most cases.

What's terribly sad is that shopkeepers will assume someone is stealing for having their hands in their pocket.