Let me ask you a question: if you lived a miserable life, and you could break the law and live a good life for five years, would you break the law? Probably.

I know there are literal alternatives to illegal immigrant detention, but what are the alternatives that still discourage illegal immigration?

From your PDF, there is a 20% likelihood that I can evade deportation.

With 40K people crossing per month (or whatever it's at now), that and assuming that half are crossing for economic reasons (i.e., not political safety reasons), that's 4K people per month that will remain illegally _after being processed_. That's a heckuva lot.