+1(514) 937-9445 or Toll-free (Canada & US) +1 (888) 947-9445
Leon said:
It would not risk the PR process if somebody was turned away at the border but if you end up getting flagged in the system, it makes visiting a lot harder. However, once you get the PR, you are ok.

Or worse - banned from Canada for a year. There's nothing like a one year ban to mess up a PR application.