The RCMP does not determine the meaning of legislation. Judges determine what the law means.
Think about it. What if an RCMP or another bureaucrat writes an erroneous statement of law? Say this erroneous statement of law is provided to you in the form of a letter. Will this letter bind a judge?
Can you imagine a judge, say, in the Supreme Court of Canada saying, “Having reviewed the legislation and listened to counsel from the defense and Crown, I find that the magazine is a prohibited device. But the RCMP said the magazine is “ok,” so we will go with that.”
I think there are two issues being confused in this thread. One issue is: “Do regulatory officials determine what is lawful and what is illegal?” The answer to that is simply “no, the courts do.”
Another issue is, “if I act upon the written advice of an RCMP official, and that advice is faulty, can I be convicted of an offence?”
Please note that officials can and do give erroneous advice. For that matter, the ruling of one judge may be over-ruled by a higher court. Thus, the determination of a lower court may be found to be erroneous by a higher court. However, in cases where a person has acted upon advice given to him by a regulatory official, in this case the RCMP, there is a lawful defense know as “officially induced error.” The principals read like this:
“The defence of "officially induced error" is available as a defence to an alleged violation of a regulatory statute where an accused has reasonably relied upon the erroneous legal opinion or advice of an official who is responsible for the administration or enforcement of the particular law. In order for the accused to successfully raise this defence, he must show that he relied on the erroneous legal opinion of the official and that his reliance was reasonable. The reasonableness will depend upon several factors including the efforts he made to ascertain the proper law, the complexity or obscurity of the law, the position of the official who gave the advice, and the clarity, definitiveness and reasonableness of the advice given.”
In certain circumstances, and perhaps even in this case, your letter from the RCMP might work as a defense. In that circumstance, a judge might enter a judicial stay of proceedings, and you may not be convicted. But consider all the elements that must be proven. Consider that judges are also human and may find you to be guilty, because your defense has not been made out to his satisfaction. In that case, you will be convicted. But even if the defense works, and the judge does not convict you, then consider what you have in store, traveling this road.
If you have a magazine that appears to be illegal, a cop will arrest you and simply ignore any letter you provide from the RCMP. At best, he will staple the letter to his file and proceed with the charges. You will be forced to pay tens of thousands of dollars in legal fees. If you win at the lower court, the Crown may appeal. Tack another fifty-thousand dollars on top of your legal bill.
So, if you want follow this course of action, then keep your letter from the RCMP attesting to the lawfulness of your actions. And take an extra fifty to seventy-five thousands dollars out of your petty cash reserve and keep it handy. Then pray that you own lawyers does not screw up your case.
You should be fine.