If I walk into a brick-and-mortar bookstore, I'm doing it with the intention of compensating them for their service - being tangible. I know the book will cost me more then if I bought it online. Anyone does. But I've decided the convenience of perusing the book in person is worth it.

But this just seems... well, wrong. Like you're violating a social contract. If this becomes more pervasive, you're basically telling the in-the-flesh bookstore to confiscate your (and everyone's) phones and electronics on entry, as it's the only way to discourage this behavior.

If you're going to treat the store as a your own personal library... at least go to the library. It's only fair.