Just get all the detail, and ask for the guest to provide ID on arrival, do everything you can think of to avoid cancelling. With luck, if it is a dodgy guest, they will cancel themselves rather than prove ID and you will be out of trouble.
I just had someone book with a profile name which was a colour. I asked if it was her first or second name (hello, Blue?) and she said neither, it was her ''profile name''. I now have her real name. New guests often don't get what they have to do when joining.
If you cannot be satisfied things are A-OK, then I see no other alternative than not letting the guest come but if you can, remove IB or this will potentially happen again and again.