scotty37 wrote: I usually start writing down their number and name just for giggles, makes them think about why they pulled me over as they don't like that.

Most coppers don't give a shit. Hell, I even offer to write it down for them!!
The classic is always the dipshit who wants your name and number and then wants to use your pen... uh, No!
Marty, the others are right. In Aus a cop can stop you simply to check your licence. Which I personally think is fair enough. The number of tossers out there riding bikes without a licence is staggering and only serve to give the rest of us a bad name. You wanna ride a bike? Go and get a licence like the rest of us.
Other than that, there may be some corporate directive to conduct checks on bikes. There may have been a spate of stolen bikes. Maybe there has been an increase in the number of complaints with regards to the way bikes are being ridden in that area or an increase in the number of motorcycle crashes. Did you ask the copper why he stopped you?
As for the total unfriendliness thing.. who knows. Sometimes it's just easier that way. As soon as you start being friendly with someone, it makes it a million times harder to write them a ticket or defect them. It's easier in the first place just to be a cunt.