I think this is an entirely made up concern. We already have this now, in practice. It doesn't remove any tools that already exist. They can pretty much deny TRVs to anyone they like. (Yes, removals are still an issue - agreed).
But if we're going to fantasize about how much governments in future are going to be concerned about 'justifying' a policy, sure.
I don't see them overly concerned about justifying the existing overly punitive and harsh approaches to (in many cases inadvertently) neglecting to disclose a common law spouse, or the revocation of PR status for protected people who travel back to their country of origin (in many cases years and years after they faced any risk, e.g. when they really do not face persecution anymore etc. I'm not defending all such revocations of course, but now it's used as a blunderbuss).