Under the convention, a person who is in need of protection can apply to a state to be recognized as a refugee. Until people are recognized as refugees, they can't be sent back to their home countries. They are treated as refugees until a determination is made. When a determination is made that they are refugees, it's a declaration of a status they already have. That's how it's looked at in international law.
We don't treat refugee claimants as criminals, and we never have.