And now to address the actual thread topic...

We have our MG at different houses, and sometimes people offer to help pack up (or start to anyway), and sometimes no one does. When they come to my place, I expect the mess, but I don't mind if they help pack up or not. I try and remember to offer to tidy up most times, but if DS has started getting crabby and it's clear he just wants to go, well then we just go. And you know, quite often when I offer to tidy up, or start doing it - I get told, "Oh don't worry about that".
When the mess is at my house, I don't mind - it doesn't take long to tidy up anyway, and it sure beats doing the dishes or scrubbing the toilet, lol.