I'd disagree with that, as that sort of enforcement doesn't fall within the jurisdiction of immigration or customs. Let's say I did come back to Canada to access the public health care system. Even if I told that to a CBSA officer at the border, there's little they could do with that information beyond tip off the police that I might at some point in the future do something illegal. They wouldn't be able to stop me from entering Canada because I have a right to do so as a Canadian citizen, and they couldn't arrest me because I hadn't brought or done anything illegal.