You don't seem to have grasped the fact that these people don't want to be in Turkey
They want to be somewhere else, or perhaps other people want them to be somewhere else so they can make a fat profit out of them.
If the constant dangers of shipwreck etc are not enough to deter them then the prospect of being returned to Turkey which is s much better option than that, is hardly likely to.
If you're into 'deterrents' why not do it properly and advocate the deliberate sinking of their boats :-)
I understand they don't want to be in Turkey, but if we know they have come from Turkey we should not give them the choice,
once rescued, take them straight back.