That's ridiculous!
I've been on lots of car cruises, events, etc. with cop presented sometimes with car clubs. After that, I drove with marked/unmarked vehicles at the rear as well and never get stopped.
I am pretty sure "THAT OLD COUPLE" made up their side of story (like noisy/low race-inspired hoon cars in THEIR area). Just ridiculous, unless you are caught doing burnouts and stuffs with photos evidences.
I feel sorry for you, Michael. Hope you don't get copped all the time and we should take this up against with whoever get involved. This is a discrimination for Japanese import drivers.