No, but you are to make a “reasonable effort”
Least case you should ask and observe stuff like body language, license plates and stuff that makes you go Hummn.
No law in my town that says I can’t cross the street anywhere I want in my town, but I sure wouldn’t do so with out protecting myself by looking both ways before I crossed.
It’s about protecting yourself, I know for a fact that there are LE trying to make buys online.
Don’t be willingly ignorant.
Where does it say "you are to make a reasonable effort," and what does that even mean???
Personally I don't care what adults do in private transactions whether it's firearms, cars, or your pet snake Bobo. But since we're on the subject...
In looking at the two sides of this coin, it seems to me that the side that's really coming closest to running afoul of Unconstitutional laws is the wannabe FFL side checking IDs and conducting many firearms transactions without a license.