Relying on timings for this type of thing is impractical because you'd have to sync the time to the nanoseconds and wireless is notorious for being noisy. It'd

Relying on timings for this type of thing is impractical because you'd have to sync the time to the nanoseconds and wireless is notorious for being noisy. It'd make it more expensive too. The most practical one, I think, is to make it NFC-near instead of BLE-near. Or, you know, just use a non-contactless one. Or add a button.