In the long run, it would be far cheaper to do what France has tried doing with its waves of illegal Muslim immigrants. France has deported them with a relatively large sum of money -- $10,000 U.S., I believe -- with the provision that, if they ever return to France and get caught, they really will go to prison for a long, long time.
Think of it as like a "loss leader" in the retail business. :>) It really is like a "get lost" contract. But it makes a whole lot of sense.
Now, in those basket-case Muslim countries from which people are illegally immigrating to France, or in our case, in Mexico and Central America, etc., where our illegals are coming from, $10,000 is a fortune.
So these deported people go back where they came from and they are set up to go into business and help their home country's economy and so forth.
Meanwhile, $10,000 is a drop in the bucket compared to the $100,000+ that American taxpayers have to pay to educate the child of an illegal alien in our schools, K-12 (13 years x at least $8,000 per year), PLUS the free maternity care in our hospitals that we somehow are forced to give them, free health care, the drain on our law enforcement and corrections systems, etc. etc.
For $10,000 we could be RID of all those unwanted and unproductive expenses and get RID of some of these bad apples.
You have to spend money to make money or in this case, save money. I'd be for it -- as long as enforcement of that prison term if they violate the contract is guaranteed and carried out.