Anything that helps the conspicuity of a hazard to aviation, as tall cranes obviously are, is worth considering. The number of cranes springing up all over London is quite alarming. A good sign for the building trade and economy no doubt, but not good for helicopter pilots who have to cope with them on a daily basis.
However, FLARM, TCAS and other such devices are only designed to alert pilots to the fact that there is something relevant in the vicinity and he should look out. The avoidance has to be done visually. Lighting that actually stands out is the only way when the aircraft has to be flown in close proximity to an otherwise difficult to see obstruction.