A little piece of advice. Never give your home number to someone you don't know, only give a cell number. You can find out pretty much
everything about someone if you have their land line. Previous addresses, schools they attended, age, and on and on... all you have to do type the number into a search field, and presto!
As for knowing a person is single, we simply take their word for it. No interest in doing background checks -lol! If it doesn't pass the "smell test" we decline, but as was already mentioned, if they are good liars there's no way to know. Going to an on-premise club makes it easy for a cheater, I would assume.
On the flip side, if you've only just met at a club, how do you know a couple is married to each other? (There are swing couples who are in fact cheaters, married to different people. We've met a few who've admitted it freely.) It's a little puzzling how some -singles and couples- we've met are completely upfront about their cheating. Have to wonder, if they are lying to their spouses, why tell
us the truth?