Hasn't happened to me, yet. Honestly sounds like someone desperate for money.

yup, had it happen, AND comments offering to color pics i've commissioned

I admit I've done that, but it was either art I commissioned, or of a particular friend's characters, with that friend's agreement. And, in all cases, with the permission of the original artist.

I've had someone asking if I want to give them a gift. They then proceeded to give me details on their character, link to their refsheet, and asked to have their character raping someone else's character. Quite specific on the details they wanted in the rape scene, too. Needless to say, the other character is not theirs. I was tempted to launch on them, but my better angels smacked me with a clue-by-four until I agreed to simply reply with (a) I'm not taking trades, requests or doing gifts right now, and (b) I will not use other people's characters unless you get that other person to note me directly granting permission.

I suspect I won't hear anything further from them.

Oh, I just replied that I didn't know them and that they clearly didn't know me and then added them to my blacklist. I have real shit to deal with and I just don't need the drama of explaining shit to them.

I should probably blacklist them, yes.