Also looking at how they are checking for them (removing the seat to look at the bottom bracket), it occurs to me just how easy it would be to have the thing fitted and installed through the steering tube before it is joined, fit an inductive charging coil and the thing should never even be needed to be accessed over the course of a few months of riding, even the charger could be obscured into a bike frame they store the thing in for the night,
It would pass there current tests, and be obscured from thermal imagers by the riders own legs reflecting heat off the frames, and if i can dream this stuff up in idle thought, then what about pro cycling teams who have money to throw at very custom bikes?
next thought, how do you activate the thing? most riders can comfortably skip a gear and still be in there power band, the bike can directly measure cadence, and could pick up GPS for speed, so if the rider has been in a specific gear for a few seconds engage, or something to that effect,
Dipping deeper still, the brake and gear changer cables are fed down the steering tube, so they could directly measure when the brakes are being applied to start charging, and directly what gear they are in, skipping the gps stuff entirely,