I don't know what the US congress is any more, but in other countries it's because they really really want to expel someone and the deportee's home country might say "no thanks, they're your problem".
A company I worked for announced that it had come to management attention that staff were socialising in the office, and that wasn't allowed. To prevent it the doors would be locked until ten minutes before our official start time in the morning. I showed up at 7:30 the next morning for my shift and the whole team were milling around the front door because they couldn't get in. Seems like they never delegated a manager to open up for us.
The policy was never rescinded, but they never tried enforcing it again either.
A patient escaped his police escort through a crawlspace above the showers. The whole building went on lockdown (with loudspeaker announcements about not interacting with any naked men you come across) before they eventually found him a mile away, still starkers.
I'm getting into Adrian Tchaikovsky myself. He certainly loves painting the future as a capitalist hellscape, doesn't he?
I'm part way into Shroud, where whole solar systems are being strip-mined for resources, and the people doing the work are skinny because they can't afford to eat well but they get auto-dosed with drugs to help them focus when hunger is distracting them.
Good: I have free speech.
Bad: You have free speech.
I think that sums it up.