witch hunt?

I was listening to NPR this morning on my way to work and heard a story about a program they're using to keep track of aliens in the US. I was hoping it was referring to little green men, but sadly no. It talked about how many non-citizens in the country are wearing electronic anklets and have to check in with some security company "or else". I guess they have a choice between being detained or wearing the anklet and being able to go home. I guess it's a trial run program, but they were saying that if it's "successful" that all non-citizens might be required to wear one. WHAT? I'm all for keeping the country safe, but since when was America about treating people who come here like prisoners? Not cool. There has to be a better way.