Possibly because all the UK military helicopters can fly unrefuelled from the East coast of the UK to the West coast of the UK, whereas none of the US military helicopters can fly unrefueled from the East coast of the US to the West coast of the US.
Possible, but it would seen doubtful. It would be a LOT cheaper and easier to simply land and refuel on a CONUS helo cross country flight than to hit a tanker. CONUS helo tanking is done mostly for training, not for range. But for long overwater flights (or long flights over hostile territory) AAR is pretty much a necessity. It's why the US Coast Guard has C-130 tankers and AAR capable SH-60s to enable long-range SAR.