Most of the ones I know, go under a work visa; and they do the work, and they do the missionary work additionally. In my opinion, this isn't deception.
If they're entering the country under a work visa, and don't do the work, only doing the missionary work....If they're specifically told they cannot come into the country and evangelize, and they say, "no, we won't do that," and then go do it....
Then yes, I think we should call those missionaries home. They lied. They deceived. They're wonderful examples of Christ, eh?
If you can show me one scriptural example of Jesus or the disciples saying, "no, we won't do that, and we'll abide by your rules," and then doing it anyway, I'll happily rescind my point of view.