Prison? (but we have to feed them) and deportation might deter others.
"We have to feed them" - What you'd rather? Let them starve?? Jesus...
I always wonder how thoroughly people manage to overlook the fact that someone who's desperate enough to jump overboard or endanger their lives in small inflatables must have been in hardships beyond our imagination. Of course, threatening crew is not OK, but it's a human tragedy still.