I think after a few years of hosting you begin to sniff out problematic guests after the first email exchange with them. It’s not so much what they ask, but how they ask for it. Or even some cases don’t even ask! There is a huge difference in attitude between someone who says “we read that your check in time is after 16:00, but our plane lands at 12:00. Would it be possible to check in a bit earlier, or if that is not possible can you suggest a place where we could leave our luggage.” For this kind of polite request, we’ll definitely try to let them check earlier if possible, or offer to store their luggage.
But when someone writes “I will be arriving at 9AM, I hope you don’t mind”…(happened to me a couple of times!) then the answer is “I’m sorry, but we have guests leaving the same day so we won’t be able to accommodate you before check in time, which is 16:00.” Because yes, I mind! And because someone who feels so entitled as to not even ask if they can check in earlier, is going to be difficult. And it’s true that with that kind of guest you had better put barriers in place right from the start.
I had someone like that book a few days ago for November: she wanted, or rather - demanded! - to check in at 2 in the morning, and wanted to check out late! I told her politely that the person who does the check ins cannot be expected to cross town in the middle of the night, and that the option I offer in those cases is to send a trusted taxi driver to pick her up at the airport with the keys. This is something which doesn’t cost them a cent more than they would pay if they took a taxi on their own. The woman in question grudgingly accepts it and then asks for late check out, and says that she’s stayed at other places dozens of times and the hosts were “more generous”!!! That riled me so much I suggested that maybe my apartment was not a good match for her and that we definitely could not let her stay after the official check out time, so that if she wanted to cancel I would waive the cancellation fees.
So she canceled, adding that she absolutely looooved my apartment and would try to book it another time. I didn’t even bother replying (although I was tempted to say no thanks), and felt sooooo relieved that she wouldn’t be coming.
Basically, you have to keep your ears and your eyes open when you discuss with future or potential guests. Usually they show their stripes very early on, and sometimes when you catch it early on, you can avoid the unpleasant ones altogether. I’ve developed a few techniques to get rid of unwanted future guests when their enquiries send alarm signals!