And might I add there is definately a correlation between how new your aircraft is and its likelyhood of being driven into. In Our company, we have had a number of new aircraft and it appears that every one has been driven into within a few weeks of arrival (in one case it was a few days). Once the aircraft are a bit older it seems that it is no longer worth the groundcrews time to ram it and they seem to be okay. Perhaps it is like the attraction of shiney new cars which causes birds to s**t on them once they are washed, perhaps shiney aircraft attract ground handlers like a moth to a flame.
Not sure its got anything to do with speed though, often into MXP and FCO and the ground equipment there has a minimum ground speed of around 50mph +...the fuel tankers are very impressive as they lean into the bends at that speed it has to be said
