i spoke to my insurance company today about this 2004 blade im picking up next week… they informed me that its insurance group 17 when its new but as soon as it becomes used it is insurance group 20… surely that makes on sense at all…
Could, sort of. Certainly the case with older super cars.
First buyer shells out big beans and looks after it, rides it sensibly because of the investment.
Subsequent riders have less invested so ride “a little” differently. If they don’t re group it, they raise the ante on the excess.
Riders of used bikes probably fall into a lower socio-economic group or something - rougher addresses, habits, lifestyles etc. . . 
Don’t pounce all at once - all my bikes are used. . . 