The grounds to give discretion to the minister in this regard were not specified.
One of the concerns is that if you begin to specify particular grounds in the statute, you limit the agency to those grounds and those grounds alone. At least that's the argument that will be made by people in court, that if you're finding some other good reason to deal with someone in this way, you're not allowed to do it because Parliament specified the only few reasons why you could.
The other concern that does arise is the presumption that if you put this into the statute specifically, that is then a statutory decision and it can be judicially reviewed, and the experience, at least with CBSA, tends to be that the more judicial reviews you have, the more time these processes take.
I hope that's helpful.