Let's start by clarifying what insurance companies can and cannot do. Motorcycle insurance policies are contracts. The terms of the contract are either regulated by law and universally applicable to all Ontario policyholders, or are specifically approved by the Financial Services Commission of Ontario to be applied in specific circumstances by insurance companies who have asked for and had approved those specific terms. In other words, there is nothing arbitrary or subjective about the way that Ontario motorcycle policies are underwritten.
And for the purposes of simplicity, we'll leave Physical Damage coverage of the motorcycles out of the equation and assume that this discussion is of basic mandatory coverages since obviously you CAN have more than one motorcycle stolen, vandalized, burned, or knocked over at the same time.
And we also want to point out that, if you increase the coverage levels of your Accident Benefits, the additional premium for the buy back or enhancement is only charged against one of your motorcycles (or cars). Which is precisely what you would want to happen.
When you insure a motorcycle, anyone who has your permission and is legally entitled to ride, can ride your bike. That includes anyone with any level of Ontario M class licence (M1, M2, M), visitors from overseas carrying the applicable international drivers licence, visitors from the United States whose licence is valid in the same manner... and provided that the person in question is not impaired or similarly barred from operating a motorcycle under legal provisions, the insurance policy would have to cover any insured losses that would occur while that person is operating the bike.
There is a form that the owner and specific persons can sign that specifies that the specific person is excluded from riding a specific motorcycle. This form is called the OPCF 28A.
There is no form that an owner can sign that stipulates that no one else can ride his or her motorcycle. This is the critical point in this article; both of your motorcycles can be ridden at the same time, one by you and the other by your sister, or one by your neighbour and the other by some guy who happened to walk by and you decided to lend your bike to.
In other words, if the insurance company gave you a 90% discount on bike number two, they are helpless to prevent you from simply letting someone else ride it, because they cannot change the wording of the insurance policy to stop that from happening.
It's a two way street. The insurance policy has to protect both parties to the contract. If insurance companies offered a 90% discount on bike number two based on an unenforceable 'promise' not to lend out the bike, everyone knows that there would be enough people with flexible morals who would take advantage of the situation by grouping a bunch of their bikes together and sharing the significant savings. The resultant losses would put the insurance company out of business or would result in a shortfall of funds to cover claims.
So to be able to allow insurance companies to offer such savings for multibike policies, there would have to be a change in the insurance contract at a legislative/regulatory level, and frankly, there is probably not a lot of eagerness to do so since such a stipulation would not solve the fact that even excluded riders can collect certain Accident Benefits.
So yes, insurance companies get it. They know you can only ride one motorcycle at a time. But you still have to plate and insure them separately. There are some savings involved in insuring more than one motorcycle, and that is how it will likely remain for the foreseeable future.