As for your defence, I donÃƒÂ¢Ã‚â‚¬Ã‚â„¢t think you have one. The MTO may have made an error, but I donÃƒÂ¢Ã‚â‚¬Ã‚â„¢t think the Courts would see the traffic stop as some gross violation of your rights. The officer was acting in good faith, and such a stop is typically considered a relatively minor detention. If the stop was based on racial profiling, etc., you might have a charter argument.
IÃƒÂ¢Ã‚â‚¬Ã‚â„¢d look into what happened with your validation. Do you own multiple vehicles? If the sticker was registered to the wrong vehicle, youÃƒÂ¢Ã‚â‚¬Ã‚â„¢ll need to correct that with the MTO. Stickers are not interchangeable, they have to go on the vehicle that they were purchased for. Sometimes their databases are simply down when you buy a new sticker and it takes a few days to make it onto the system.
The offence that youÃƒÂ¢Ã‚â‚¬Ã‚â„¢ve been charged with is quite minor. IÃƒÂ¢Ã‚â‚¬Ã‚â„¢m sure if you met with the Crown, theyÃƒÂ¢Ã‚â‚¬Ã‚â„¢d offer you a reduced fine for a guilty plea.
NOTHING I SAY ON HERE IS LEGAL ADVICE.