Hi Kirsten,
I may be late on this, but I think you could be shooting yourself in the foot if you post something verging on the perceived negative.
I would leave it short and sweet. Focus on the good (there is no bad - just a perception that maybe, perhaps soemthing sinister was going on), but as a host you should not be judging people lifestyle and behaviour. As long as they abide by the rules then no harm done. Should you get too wordy on judging them, you maybe scaring away potential guests. You are focusing your message so much on that they did, their movements and movements that you expected but didn't happen. You are judging. Potential guests may see you as a busy body, interfering and nosey.
For the record, my experiences with students, the younger generation is always very positive. Much more than the business men that come through for business or the trade fairs. I find the students far more conscious of their reputations in the internet and are aware of its potential.
Good luck and relax a little.
Peter