Wouldn't said stupid customer have contacted your shop to send your FFL information to the seller ?

All the FFLs that I have with (via telephone or in person) have taken all the pertinent information, where to send their FFL information to, who it is coming from (be it individual, or another FFL) what I am having sent to them, my name and contact information.
They document all of this, and when the seller sends me the shipping information I update my FFL. And when the firearm arrives & they do what they need to do, which includes opening the box to verify what has been received, I get a phone call to come a fill out the background check and take home a new toy.

So as far as your rant goes, I see this as a failure on your shop, not as a stupid customer.