I think the whole idea of couchsurfing is that you're supposed to be more integrated into the culture, and exchange a place to stay for stories/companionship, but I imagine lots of people use it as a free hotel. (I've never couchsurfed myself but had a few people stay over.)

I've also often heard anecdotes that people who get things for free tend to be more demanding than people who pay for them! I don't know why this is. But I imagine that might hold true for couchsufers as well.