I don't want to watch 30s of publicity for something I don't like and will never buy (and it could even make hate the brand). But if you insert in the video non obnoxious product placement I can live with it.
Example : I watched a cooking recipe yesterday. The cook emphasized 2 or 3 times the brand of flour he was using and that's it. I understand he needs to make a living (he's a pro, not a home cook) he was not obnoxious about it, I'm OK with that. I even have a more positive view of the brand he was advocating since they are clever about their publicity.