Under the FDA regulations even though they are a beginner you cannot "manufacture" for them by helping them to set it up (touching or installing batteries, messing with coils, etc.).
However, once purchased aren't the items no longer yours and now owned by your customer?
So the customer gives the items back to you, the shop owner, after purchase...
Can you help someone in your shop to set up their equipment in this way?
It's no longer yours, after all, you the shop owner no longer posses the item.
In our case we have videos to prove this as well as detailed times and dates in the cash register and on the receipts.
I speculate that once the change is returned to the customer you, the shop owner, is no longer covered by FDA regulations because the items in question are no longer in your inventory and you are no longer selling them.
If this were not true then hanging out behind the convenience store for a smoke could cause problems: the clerk gives you a light and suddenly the convenience store owner becomes a "manufacturer."
If you don't own an ENDS system, is there a problem with you touching it? Changing it?
How is this different than the convenience store clerk taking the wrapper off your smokes and throwing it away: the clerk and convenience store owner would, under this logic, also be "tobacco manufacturers."
Perhaps the new owner could "hire" you personally to fix their vape?
Give you personally a fiver to set things up.
On the other hand the FDA could claim the "vape shop" is somehow magic and these thoughts and ideas don't apply.
Again, though, it would also apply to throwing away the wrapper from a pack of cigarettes.
What if I go to your shop? Can I help someone in your store?
What if I have contract employees, i.e., people in my store who are employed say, by a temp agency, and not me, the shop owner? Could they help a customer?