What happens if I don't pay a traffic ticket?

I have been told by Chinese friends that some traffic tickets, depending on who issues them, can actually prevent you from leaving the country if left unpaid. Is this true?
My scooter is registered under an old address and it is highly possible that I was mailed a few of those “photo included” tickets but never got the mail. Since many times they don’t actually put a ticket on the bike, I may be looking at a few unpaid traffic tickets.
Where can I check on my outstanding tickets? Is it true that they can stop you at the airport? How does this ticket doubles system work (what kind of ticket can double and what’s the max amount it can double to)? And what can they do (aside from stopping you at the airport) to make you pay up?
This has made me edgy since I’m planning a trip soon…has anyone been down this road before? Thanks.

They do this users.ev1.net/~hjahangiri/person … l-bird.jpg

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There’s a phone number you can call to an automated(?) service where you punch in your reg. number and it tells you how much you owe, if anything. Have one of your Chinese friends look it up for you.