In principle I don't think I have a problem with some sort of re-training or competency test if you've been off a bike for a long time.
I'm a classic example. I passed my test in 1980, rode bikes until 1983, and then didn't ride one again until 2004. When I started looking at bikes in 2004 I was surprised to find out that I could buy any bike (a 180mph GSXR 1000 for instance) and ride it away from the shop with absolutely no refresher training.
I'll admit to being a bit wobbly on my Speedmaster until I'd got a few miles under my wheels, but at least I was sensible enough to have it delivered to my home, and to ride those first miles on roads that I know well, and that aren't very busy.
If I'd bought a GSXR1000, and got on it outside a shop in the middle of a busy city I think I'd have been a danger to myself and to everyone else on the road. If people are doing that then perhaps some compulsory re-training or testing wouldn't be a bad idea.
