Lie back and relax, it's going to happen.
I think El Reg is behind the curve here. Reverse powering of remote equipment already has a European standard, TS 101 548, published in Sep 2014 by ETSI the European Telecom standards setting organisation. http://www.etsi.org/deliver/etsi_ts/101500_101599/101548/01.01.01_60/ts_101548v010101p.pdf
It's not some group of nutters proposing this. All the European Telcos and manufacturers have got together and ratified this spec. Anyone can make equipment that meets this spec. and legally install it on the public telecom network. Safety is covered by the usual EN60950 spec. used for all telecom equipment.
Texas Instruments have published a design note for a 12V 1.2A power supply where up to 8 users can share the powering of one DPU but it must function with power from just one user.