Unfortunately that's not how it works in reality. A rejected refugee claim pretty much guarantees that all future temporary visas to Canada (i.e. visitor visa, work permit, study permit) will be refused. Nothing is stopping the person from applying - but refusal is almost certain.
A withdrawn claim isn't quite as bad but still problematic and will likely cause issues in the future. We had someone here not too long ago who entered Canada on a study permit, filed a refugee claim, then withdrew it and returned home. Then applied for a new study permit to return to Canada and complete his studies - which was refused due to the refugee claim.