I do the same thing on my bike if I'm being tailgated. It's always worked so far. If I get an a$$hat that doesn't get it I'm not going to challenge him or slow down on my bike. Cage, maybe. I'll just find a way to get away from him on my bike. Like Hyde said, no health costs here in the Great White North, but I don't want to end up in the hospital.If I am being tail-gated when driving my car, I no longer worry because the crash (if they fail to stop when I do) will be gentle. If, OTOH, I have somebody up my arse when riding, I slow down*, turn around, give them a stern eye and wave them back. Only once did I have to do it twice, the other times the followers have slowed right down. Ladies often give 2-300 yards of room afterwards.
*If it is a truck/semi/bus etc., I either speed away if I can, or turn off the road and let them past - I do not need an angry truck driver with 25 tons of steel following me.