Various schemes like that have been evaluated before, but discounted on the grounds of safety. If you cut the power at the wrong time when the rider doesn't expect it, it could be very dangerous, but if they're only going to cut the power when entering a pedestrian zone, it might not be such a problem.
As I said before, the Auditors on YouTube are discovering new data centres with massive security all over the place. There are soon going to be a lot of personal rights taken away. Why do you need security at a data centre? You can't steal the data, and it will surely be backed up somewhere else. The only thing that makes sense is that they're covering the risk of the place getting stormed by people on foot, but why would anyone want to storm the place. See for yourself. When he went to a bank's data centre, they didn't have a tenth of the security this one has: