Theoretically this one should have demerit points. O. Reg 339/94 prescribes demerit points, and for a couple of municipal by-law infractions, you can get demerit points. In your case, offences under section 143 and 144 (9) of the HTA, and "any municipal by-law prohibiting turns" (including u-turns) is supposed to have 2 demerit points.
However, MTO may not find out, because it is a by-law infraction. I don't know how good the city of Toronto is in notifying MTO of traffic by-law infractions. If it is HTA, it would definitely go on your driver record and you would get points. That said, your insurance company probably wouldn't find out, because it is not an HTA, CAIA or criminal offence and should not go on your driver abstract.
* The above is NOT legal advice. By acting on anything I have said, you assume responsibility for any outcome and consequences. *
http://www.OntarioTicket.com OR http://www.OHTA.ca