Yeah, they can amend the ticket to reflect the actual charges. Even if your ticket was actually the wrong location (like the wrong street all together), I think it's a difficult case to make unless you could have actually proved that you were never on that street with that vehicle. I don't think the wrong street is a fatal error anyway though, so they could still convict you. It really depends on the JP, I've heard of tickets getting thrown out because there was a spelling error in the name... Courts are crowded, JP's just throw stuff out for small errors sometimes, but it's their discretion.
JP's are cranky, sometimes that works in your favour... Like that story of the JP who threw out all the charges because the prosecutor walked in 2 minutes late, or something like that. They can, and sometimes will, throw out charges even if they don't absolutely have to. So just because it worked once, doesn't mean it will work again, but it doesn't necessarily mean it won't work again - it's all up to the JP.
Link to the article about the cranky JP mentioned above:
http://www.thestar.com/news/crime/2013/ ... _late.html
Edit: Just briefly read the article again, I find it hilarious that it starts with "An impatient justice of the peace tossed out more than 60 charges en masse because the prosecutor was two minutes late, costing the city lost revenues and prompting a battle with Torontos legal department."
Reinforces the idea that traffic tickets are the City's cash cow.
