Regarding ethics, I've always steered very clear of small businesses that prominently display that Jesus fish. It's been my anecdotal experience they will NOT be someone you want to deal with. 


I'm sure some are fine; I've been burned too many times. Now it might be used by bad apples as a "shorthand" to people fooled into thinking Christian=good, and not mean they are actually Christians, but I don't really care to understand the why behind it.