There’s also this guy:
Apparently it has a 18" read range with a standard RFID card. Let’s say I get half of it with an implant, it could easily read my butt from under the seat. Or my hand from under the desk possibly, for that matter: as it happens, I already have an EM4305 chip in my right hand.
I think I’ll get me one of them boxes and try it out with my hand: If it works from under the desk, problem solved. If I feel it could work well enough from under the seat with less implant movement range than with my hand, then I’ll order another EM chip and I’ll make the embarrassing call to my piercer 