Honestly, bike registration isn't that terrible, but having to affix a license plate to the back of my bike is. I can honestly see people getting arrested at CM because their license plate blocks their rear taillight. Even if arrests don't result, it's still unsafe because on most bikes it WILL block the taillight.

That said, even if they came up with a viable alternative I would be against it, if only because there are so many people who bike only occasionally who will probably give it up all together instead of dealing with the hassle of registration.