Common practice in Canada. It's in our ops manual,totally legal, idle, frictions on, we are able to hot refuel, load freight, pax etc. No way am I shutting down for fuel on the likes of Baffin Island, in polar bear country at -40c and a good chance no human habitation within 100's of miles. Very lonely feeling hauling up to Alert in probably some of the most inhospitable terrain in the world. I probably see no reason in the UK or Europe to be hot refuelling rotors turning, but Utility in Canada yes for sure as long as it's done safely.
Same as Nubian, most my 15500+hrs on the end of a longline in the HV curve. Can be done safely as long as you always have a plan and an out if it all goes Pete tong....