It would be interesting to see a copy of the letter, written by a third party (the hotel manager) responding to hearsay. I would hope that any airline management receiving such a letter would treat it with the contempt it deserves.
It reminds me of an incident when hotel staff reported a Captain for spending the night in his hotel room with a lady member of another crew also on layover in the same hotel. Red faces all round - the lady was his wife!