If they don't know who your "ex" is, tell them that it was your "ex"(baby-daddy); and that, you had to talk to him for business purposes.
Following on from Jourles and LT: What did you discuss? Was there any physical contact between the two of you? Did you arrive and leave in separate vehicles? Who paid for your meal? Where did you go after your meal? Once again and this is very important, did you arrive and leave in separate vehicles? We're just concerned about your spirituality, sister!
Gosh, it's been so long now I would just act like you don't recall what they are even talking about (if they do ever question you). If they try to "refresh your memory" just look blankly at them and say, "are you sure it was me?" and make a really confused face. Works everytime ;)
They don't give a crup about your problems but if they sniff "a sin" they'll run like a good puppy to their master with tong stretched to ground yelling your name, that’s how they cover their own tracks. Because hey if you are soo good in reporting others there is noooo way you yourself would do something like that, right?
Someone told me the other day about a J-DUB lady (admittedly according to them on "fringes of the truth") coming out of casino. Actually, what dog reporting her failed to check was that there was a restaurant in the same building, and if you wanted to go to toilet you basically had to go through casino. What escaped everyone though was – where the hell was that other sis-in-good-standing if she saw this lady coming out of casino in the first place, definitely not to far away from this “sinful place”.