At that level of competition, just keep xraying bikes so it can't become an issue? Drug testing is privacy invasive, having your bike xrayed isn't if you're not cheating.
At the top levels, there isn't much privacy already. In 2007, the GC leader of the Tour was removed from the race because they had lied about their location a month prior. Racers are required to tell UCI, the cycling governing body, their locations in order for doping controls.
Not just at the elite level either. The whereabouts system has expanded to apply to tens of millions of people, completely outside of any serious national or international legal frameworl.
It's too obvious to put the motor in the bike. What they should do is embed electromagnets under the road surface to help accelerate certain bikes and decelerate others.
https://en.wikipedia.org/wiki/Michael_Rasmussen_(cyclist)#Un...
https://en.wikipedia.org/wiki/Mechanical_doping
Article created in 2016.