Perhaps they are seen as non threatening whereas when in a line of moving traffic I've been 'surrounded' by a gaggle of sports bikes pushing into spaces which would not exist if I hadn't braked to let them in and which even I found somewhat intimidating.
That has never happened to me with a bunch of harley riders - in fact the line of traffic normally passes the harleys
Herb your comments about harley dealers set me thinking...... perhaps that's where we should all go for our m.o.t. tests? We could buy things like handlebar tassles and back rests while we were there
