I only backed out of one sale when meeting a guy. He still had his hospital plastic bracelet on and said he wanted to end it all. Yeah....red flag, and sorry I can't help with that. Had one other that was kinda sketchy, but I was hard up for quick cash a long time ago. He had a FL DL and said he wasn't prohibited, so I let the rifle go, took the cash and bounced. Got a serious bad vibe, but he was 70+ and lived on a boat and wanted protection. If he was another demographic, I would have sold elsewhere, but I didn't think gramps was exactly planning on a driveby with a beater of an A2 clone. He was just ....strange.
All my other transactions have been pretty cool for the most part. One old fudd thought he was going to convince me to let him make photocopies of my CCW and DL. I said he could glance at them, but no copies, no way, no how. He said no. After I told him I was no longer interested and got up to leave, he caved and sold me the pistol. Haven't done any other business with him since, and our state gun forum is a hopping place.
I just ask are you legally permitted to purchase in FL, and if they say yes , then cash changes hands, and off I go. No BOS, no other BS. Cash and go. This is 'merica.