@Danny627 It will likely be legit. There are two possibilities. Either the guests has been let down by a host and Airbnb is trying to re-house them OR the guest has been kicked out of a property for misbehaviour.I personally don't think it should be the latter but people have reported on here that guests removed from other properties have been passed on to other hosts.
Do you have request to book switched on for last minute reservations? If not then I guess Airbnb was just checking all was OK as they wouldn't want to et the guest down twice.