Keep in mind Will's case will probably be referenced in the future - there are many more such cases coming up. If the crown is successful and gets jail time and is able to characterize Will's retailing activity as supplying criminals with guns, this would be a bad thing for ALL of us, not just Will. There are other cases coming up and I am sure this won't be the only plea for assistance. Today, CBSA is going after retailers, but if the crown gets what it perceives to be a good conviction, they could be coming after YOU tomorrow and you may be making the same plea.
So, in the interests of airsoft as a sport, I would appeal to anyone who played around that time to contact Will and offer their assistance with his case. Nobody should be going to jail for selling what is essentially a TOY. The crown needs to get that message and understand that they are going down a road that will put sports enthusiasts and hobbyists in jail and NOT criminals.
Will, has the crown got criminal witnesses that are going to testify that they used products bought from you to commit crimes and were convicted under the firearms act? If so, you're fucked. If not, this defense strategy your lawyer has suggested may actually work and work in everyone's favor.