You are aware that that letter is only an internal force directive. It does not say charges are NOT to be laid. It has no significance to other police services. The RCMP do not dictate how or when a charge is laid by other services. If the mag becomes a prohibited device, which apparently is the case, appropriate charges can be laid.
Once a charge is laid, and I bet one will be, it will be up to the crown to decide if the charge proceeds. Past cases would indicate the charges would go forward.