I am good friends w/ a gun store owner and he tells me that during annual inspections the ATF would come w/ a copy machine. Then would then copy 4473s mostly which listed non-PC guns. I think they were mostly focused on ARs/AKs and the like. He said they backed off some when he pointed some of his store security cams at their table. Initially they wanted to use his copy machine. He had no idea what they did w/ the copies but had his suspicions. So it does occur.
Ok, that’s for store sales.
What about when buying via GunBroker.com and you’re just using that store’s FFL?