Exactly what The WANDERER said and just to reiterate the message...Everyone should do this and get documentation of them stating this, then if / when you get pulled over, show it to the police and or the courts if it goes that far.
If it cannot be registered as a motor vehicle, then it's not, your document now defeats anything the Crown Prosecutor has (which is diddly) for the purposes of the HTA, the criminal code is different.
Go to an MTO office all by yourself and attempt to get your modded bicycle registered as a motor vehicle and before they shoo you out the door empty handed try to get the results of your attempt in writing on official letterhead. If that's not possible take a witness and then have your witness prepare a statement which can be notarized. A video cam or a little spy cam like I have would possibly do the job too.