As well, who has the right to order a vehicle towed if it doesnt have registration. Can any person do this, or just a police officer?
In regards to towing authority, police have it under the HTA, but many muncipalities have bylaws, etc. that regulate unplated/unregistered vehicles. Some will ticket unplated/expired plates even on private property, not sure if they can also tow. Also if your parking area is shared (i.e an apartment parking lot) the property could also have your vehicle towed if they have any issues with unplated cars.
Above is merely a suggestion/thought and in no way constitutes legal advice or views of my employer. www.OHTA.ca