Not so. AFAIK none of the major ebook retailers go out of their way to mention this, and they target their marketing towards consumers who are not savvy enough to know to ask. They will only inform you of the DRM when you run into one of the limitations it imposes.
EDIT: Actually, I should clarify. One ebook retailer does make this explicit — Google. But I wasn't counting them because they don't "own" a market segment and you'd probably be pretty savvy to be buying from them anyway.
Good point. Not sure if it's still applicable, but wasn't it such that you couldn't carry your iTunes library over international borders?
If it's DRM'd then I'd expect to pay far less for it. I've got a Kindle, and I won't buy any books for it - because I feel so uneasy about where I stand on this. Which is a shame really. Add to that, that paper copies are somehow cheaper a lot of the time, and that I can pass /sell them on, after reading. Prevents me from becoming spineless.
EDIT: Actually, I should clarify. One ebook retailer does make this explicit — Google. But I wasn't counting them because they don't "own" a market segment and you'd probably be pretty savvy to be buying from them anyway.