Secondly, the "majority of guests ..." is a blatant example of argumentum ad populum, a logical fallacy. Appeal to me based on my self-interest, appeal to me based on the environment -- I may or may not agree -- but simply stating what other people are doing is not sufficient. I disagree with a lot of what other people do. Also, devices like "in your specific room" are transparent and annoying. If I checked-in to a particular room where, by sheer chance, the last 200 people trashed it, would it be then OK to do the same? That's the same argument they're using.
Oh, and one small thing, they're claiming to know why the previous guests picked up their towels up, and therefore to be mind readers since there was no survey. They can't say "well, that's the popular opinion" because they're talking about that specific room.
That depends entirely on the culture of the audience, it'd likely work pretty well on Asians because of their more collective culture where everyone cares very much what other people are doing.
You're likely an outlier, those things that annoy you might be very effective on the general populace. Honesty is not always the most effective strategy.
The thing you would realize if you read the book is that all of our normal conversation is "manipulative," in that we are trying to elicit some desired response from the other person. Otherwise we'd speak like a robot, with no emotions or facial expressions, always make pure statements of fact and never get anything accomplished.