I'll just elaborate on that. As Minister Goodale stated, there are limited authorities in terms of questioning a traveller upon withdrawal. Again, it's to ascertain their identity and their reasons for withdrawing. The expectation is that there would be a limited set of questions. Those questions would be responded to, and in most cases the traveller would move on.
To add to what Martin said, most of us can picture the airline context, where it's quite controlled and people have already provided a great deal of information before they decide to withdraw. But the agreement and the bill were designed to deal with the other modes of travel as well, where you are dealing with a different kind of context—pre-clearance at a land border, for example. Again, it's to recognize these different situations and to ensure that a fairly minimal set of information can be obtained in order to alleviate concerns around probing the border for weaknesses.