Besides the MAYDAY/PAN thing, another difference I have noted between the US and other nations is the stage at which tanker crews issue the clearance astern. The old and bold AAR mafia on here will be gratified to know that European tanker crews are still uniformly rigorous in waiting for joiners to be stabilised in the echelon position before issuing clearance astern. US tanker crews, not so much... my personal record (set within the last couple of years) is being cleared astern a KC-135 on first radio contact at 70 miles, with the crew seeming surprised when I asked whether I could join through echelon instead. Time and the investigation will tell whether the custom may have contributed in this case (noting the greater risk of misjudging closure on the slow KC-130) but regardless, it’s a cheese-hole that should be closed.