I think if you haven't got documents, and you have clearly come across from France ie by boat. We should have some agreement with the French as a joint coalition to send them straight back, then process them in France, and both countries then decide who keep them.
I know that might mean they come back to us, but let's at least have a process to discourage anyone trying to buck the system, IF that is happening at all.
I think it has to be a hard and fast rule, if you travel without documents, then you are going back. We can always make exceptions for countries where we feel they would not have had time to grab documents. I suppose it depends how often that is done, and is it a real problem or just media noise and are there certain nationalities that are doing it ie albanians etc.
I suppose without seeing what is actually going on, it's a very hard question to answer and sending them straight back, might be extremely unfair if cases are genuine. I don't really read anything around undocumented migrants, so I don't really understand what is happening, ie are they ditching documents or genuinly don't have them.
I apply the above to adults, not to minors. Always help the kids whatever, I'm mainly talking about men. I think whatever we do can only work in agreement with the French, so they will want something in return.