Here's one DIY Organiser's view:
(not necessarily AUK policy, but how it works at the moment with me.... so check with your DIY Org)
Once a rider has bought a brevet, virtual or paper, they can provide proof-of-passage through their (Advisory Route) controls by either
(a) a set of receipts (or photos of them).... not necessarily accompanied by the nice Brevet Card;
or
(b) a gps track.
So, having a printed brevet card need not commit you to sending it to the Org!
It doesn't affect the finances, because:
If the rider has bought virtual brevets, the org pays a fee to AUK when the ride is validated;
If the rider has paid for a printed card, the org has already paid the fee to AUK when buying the stock of printed cards.