The police had blocked the intersection ahead of me. An officer came up to me, grabbed my bike, and requested my license. As we talked, the street cleared out, and she moved me over toward the curb. She was more civil than i've come to expect: she actually answered me when i asked what was going on, and why i was being stopped.

Still gave me a bullshit ticket for not riding on the right or left side of the road, eventually, though.

When i pointed out to her that there was no way i could ride all the way over to the right (because there were other cyclists there), she said "You should be riding single file, then."

When i told her i didn't think that the law called for cyclists to ride single file, she said something along the lines of "Look, i'm just doing what i've been told to do."

She then took my driver's license, told me to wait there for her to bring it back, and wandered away for quite some time. I was amazed enough at the whole scene to forget to get her badge number, so i stood there in the street where she had put me. She was gone for quite some time, to the point where i was no longer sure that i'd get my license back, but as the police were winding everything down at that intersection (which they had blocked up for about 30 minutes) she came back with my license and the written-out summons.

Reading up on the Traffic Rules which i was ostensibly violating, i find that in fact, the section states (from section 4-12 (p)):

Which appears to be clarifying additional privileges for bikes (i.e. the permission to ride as far on the left as is practicable in addition to the right), not removing them.

At any rate, it would have been impracticable for me to ride further over to the right than i was, because there were other vehicles there!