That's a really good idea. We stand a better chance at helping people who aren't in control of themselves if they're contained. It would also make sense to have a place that can hold some of the more powerful enemies we might end up tackling. Back in Metropolis, they had a high security location set up in case of a super powered threat that they needed to lock away. This could be a lot like that, but with magic involved. It was mostly just tech in that particular case.
(Peter) I sincerely hope that no one is crazy enough to try. They'd only be starting a war and we've already had enough of that around here to last a lifetime.
But if something like this is being put together, it might ease their minds a little. If they know that we have something intact in the event that those people they're wary of step into enemy territory, then they may be less likely to step out of bounds.