I would be surprised if the state really has such a system to keep track of the tickets issued in all the towns and cities in the Commonwealth, especially when different municipalities use different ticketing systems. I know that Somerville just recently upgraded its ticketing system to a new vendor [link to city's press release]. I’m even more skeptical of there existing an inter-state ticketing system.

If you have any outstanding parking tickets, excise tax bills or abandoned vehicle citations, you must obtain releases from the city or town involved. You must present the original releases to renew.

this is the page: http://www.mass.gov/rmv/regs/reg5.htm

Obviously this won’t help with out-of staters, those who register their cars in other states, or those who sell their vehicles and go car-free, but would eventually force Mass. residents with cars registered here to pay up.

I also think some states may have similar reciprocal agreements with other states. My mom got a ticket here while visiting from Ohio and since it was a ridiculous one (she had the visitor’s permit on the wrong side of the dashboard, but still visible), I told her not to pay it. She said she had to or she wouldn’t be able to renew her registration. I don’t know if this is true, but she was concerned. (I successfully disputed the ticket for her, so it turned out OK in the end.)

Re boots: I have seen several here in Somerville. Though not nearly as many as I saw in Cambridge when I lived and/or worked there.

When all streets become resident-parking-only, and if higher numbers of non-residents start getting tickets, and a sizable portion of those go unpaid, and the boot system can not scale up to that volume, then the new policy will become futile. What good is an unenforceable law?

Also, what steps is the city taking to alert the non-residents to the rule change? Will an orange ticket be their notice? That would seem like an awfully rude surprise to get.