No signature is a fatal error, as well as if the set fine OR total payable is incorrect. There are a couple of ways of fighting it. If you choose not to dispute the charge (by simply doing nothing), the Provincial Offences Act then takes over, and the Justice of the Peace who gets your ticket the only has to do one thing: Examine it to see if it is complete and regular on its face. If it is, the JP will enter a conviction against you. If not, the JP is supposed to quash the certificate. "Complete and regular" basically means no fatal errors. The Ontario Court of Appeal in the London v. Young ruling (link below) stated that if there is a fatal error and the defendant either does not respond to the ticket, or does not show up for trial, the JP must quash the certificate. Problem is, many JPs don't bother to examine the ticket and simply enter the conviction, which means you then have to appeal it to get it quashed. (This is about as painless as a root canal.) Here's the case law behind it, if you're interested in reading that sort of stuff:
R. v. Monahan et al, 2009 City of London v. Young, 2008 City of Barrie v. Porter, 2007 City of Sudbury v. Leikermoser, 2008
You can plead not guilty, but be aware that if you are present for trial, the Crown can amend the certificate and fix the error... but that can be stopped as well. Check out this website:
www.ticketcombat.com
The "unproven theory" OPS Copper is referring to came from another member, who says that the simple presence of a "total payable" renders the ticket null and void. I wouldn't bet the farm on that one.