Interesting responses[^]. Not a lot of responses but then I don't have a large readership :-)
What happened the next day? Our customer contact apologised for 'last night'. I fear that I was sufficiently upset over the whole affair that I was rather less than gracious; I replied 'you should have known better'.
The apology itself was enough to assure me that I'd not assumed wrongly. If it had been, as one respondent suggested, a Kareoke bar I'm sure I'd have been derided. I wasn't.
But thinking about my response over the next few minutes I realised just how ungracious I'd been. I'd done and said little to lead him to believe that he should have known better. I'm somewhat naive in some areas; I don't go to brothels and if my friends do I'm not aware of it so I don't automatically assume I have to warn everyone against taking me to brothels. If we meet in the future and that is your bent you'll know to include me out.
So I took him aside half an hour later and apologised for being ungracious. Didn't apologise for walking out the night before. I think future 'invitations' to dinner will be just that, which will suit me just fine.
The other three are colleagues. One apologised; the other two said nothing. I said nothing either. What I will or won't do is my business. What they will or won't do is theirs.
As for my employer? Haven't heard a word on the subject.