Wouldn't unwanted criminals (illegal aliens) be pretty much the same as "wanted" ones?
Sure, although the degree (of underlying crime) is less for most illegal aliens than, say, Mafia hitmen. But it’s the same principle: They can’t go to the cops to complain about a criminal offense against them, because their own crimes then would be learned.
In medieval England, it was relatively easily for a wanted criminal to remain a fugitive, so authorities — in addition to continuing efforts to apprehend the crook — would let it be known that he was an “outlaw,” i.e., that HE could be robbed, or killed, without legal repurcussion.: he was an OUT-law. Least, that’s the way I was taught 8)