It is not illegal to mail the card.
As a PR, under Canadian law you are no longer considered a foreign national. Once you are determined to be a PR (which is why you have the PR card) the Immigration officer is required to let you into Canada without further delay.
Long story short, you're not gonna have a problem. Immigration officers have far more important things to do than ask you if you mailed the PR card or not. (Which any way is none of their business since it isn't illegal.)
Many thanks for the clarification..ill send it by courrier pigeon lol