I do appreciate clients taking a few steps in making you, the case manager, comfortable.
1. To the question is (wearing) my towel enough ... The answer would be a no.
2. Try and make space for the case manager to sit somewhere. It doesn't have to be furniture if this is an issue, of course. But it's great when there's a clear area to sit.
3. Try not to be surprised when your case manager shows up at the time you had scheduled to meet (also known as I can hear you in there...).
Though I don't expect the following by any means, I'm grateful when a client offers me something to drink. Not sure why -- it's the symbolism of it more than anything.