Actually, I read the 1-star reviews first. The thoughtful ones usually give some indication of problems. Once it passes that test, yes, I do peek at the publisher. Sometimes, I can tell from the 1-stars pretty much what the deal is with the publisher and look to verify it.
Sometimes, I'm very pleasantly surprised.
I'd like to say that I trust my close sources for books but there have been a few times where a good book was recommended, I blithely went in reading it and discovered it had a real bummer of an ending. I can handle bummer endings if I'm prepared. I wasn't. It affected me for months afterward and I was really pissed at the person who recommended it, even though it was a good book!
Just...bummer ending. Had I read the 1-stars first? I would have been more prepared. So...while I have trusted sources, I don't always take their word sight unseen anymore.