Well, you'll definitely create jobs that way, just think of all the prison guards you'll need if you do that. It'll do wonders towards reinforcing the backbone of America's prison-based economy, but then you also have to keep in mind that in
Thailand the illegal immigrant population is 1/6th of what it is in America, proportionally speaking (0.7% vs 4%). Then again, that number was before the financial crisis and the record unemployment that's happening now, after which its estimated that
millions have already left on their own.
But hey, that brings about another interesting suggestion - why not let your
bankers keep running your economy to the ground, so that there's no jobs, and therefore no illegal aliens will want to come in the first place?!??! That'd be a grand proposal towards saving the average American the intellectually demanding task of pressing "1" for English! And just like
your prison idea,

there could not possibly be any undesired consequences! =D