Yeah… this is the case for pretty much all the Virtual Line Passes for Universal attractions. The VLPs aren’t linked to a ticket or anything, so anyone can book as many as they want.
(Example: if you have a party of four and everyone has a phone with the Universal App you can potentially do both of the houses 4 times.)
A lot of vloggers were teaming up with half the group trying for House A and the other half going for House B. Then they’d be have better odds at getting both houses and do them more than once before all the VLPS were gone.
Plus, the Geofence for the VLPs is pretty large - you can even book them from your hotel room and the parking areas.