Once a detector is good, you can train a model to adjust its outputs to cause false negatives from the detector. Then the cycle repeats. It’s a cat and mouse game basically.
The only proper way I see is a system that is based ob cryptographic signatures. This ia easier said than done ofc.
But they run locally on the phone, if I’m not completely mistaken. So no use for a server.
Or do they offer this option? I think they explicitly advertise no internet access.