Ehric - I agree sometimes it's better to have no review than a bad one! But totally their fault for reading the listing properly.
I had a bad feeling when my guests asked me to write to the Home Office, but felt my hands were tied. If I refused but they kept the booking, they would have been dissatisfied from the outset which would have made things difficult. I'm not sure if I would have been justified (in Airbnb's eyes) in cancelling the booking so my reputation as host would have been harmed. Am still a bit pissed off they asked though, as it was a fair bit of work on my part and also just felt a little bit uneasy about it. Normally guests are very open about their reasons for visiting, but this couple mentioned a course, but wouldn't give any details about what it was for or where it was (I asked the location so that I could tell them how far they would have to travel to it), but still they said nothing. They are also from a country which is in the news a lot recently (not for good reasons). I didn't think they had sinister reasons for coming to the UK, but I hated their vagueness!
I've just had a notification to say my other week-long guest who was staying at the same time as the other couple has left a review too. Am a little bit anxious as she was very very pernickety about things (asked to borrow my hairdryer two days in advance, and before she stayed she continuously emailed to ask if towels and wifi were included). We ended up driving her to and from the bus station, plus gave her a very big discount on the room as it was a new listing but I still fear that will count for nothing and she'll say something which will put other people off!
I'm too delicate for this hosting business I think...
Each - I tend to do beds on a weekly basis. Month-long guests get offered a weekly change of linen, and gave choice of either doing it myself or leaving clean things for them.
Will you be allowing use of the kitchen other than for breakfast? Just bear in mind that longer-stay guests (in my experience) will end up eating a fair amount of take-aways - perhaps just have a think in advance about whether this is ok. I'm generally ok with it, but am a bit paranoid about food stains on the soft furnishings!