It is NOT illegal to mount your plate vertically in Ontario Canada. I got this right from the OPP traffic manager by contacting them through their web site:
Section 13 of the Highway Traffic Act...
Not any more. As of August 1st, 2008, its now illegal to mount your plate vertically. I'm not sure what they do though. They may fine you or they may just give you a fix it ticket. I spose it depends...
As of Jan 1st, 2011, no they are not. Vehicle Code Section 5201 states: "License plates shall at all times be securely fastened to the vehicle for which they are issued so as to prevent the plates...
no. laws regarding trailers though may vary, you will need to check those out by municipality.
what about on a motorcycle, the state trooper said it was illegal ??