To plug your phone into the wall should not be to get arrested, unless there is a gigantic sign saying "PLUGGING INTO THIS IS PROHIBITED." [...] What's more, it *shouldn't* be prohibited unless it creates problems.
You do realise that this is exactly how it was, right? There was a sign, and it exists because plugging in might damage your equipment. From TFA:
Electricity sockets on Overground trains are clearly marked with the words: âoecleaners use only and not for public useâ.
On a forum dedicated to the London Underground, members have pointed out that plug sockets on the trains are for cleaning equipment deployed when trains are in depots. They recommend not charging electronic equipment as there is a risk of power surge: âoeIf something was directly plugged into it (for example a standard computer, or a laptop without a battery in) the equipment would probably be damaged at any section gaps where the power supply changes from one substation to another!â