I read that they were giving ankle bracelet like devices to a lot of them, to keep tabs. The stupid thing is, that they are giving them to people with families. Wouldn't you want to track the single guys who could be a problem and have no family or kids to hold them back from running?
I see the migrants daily on my way to and from work.
I use Loop 375 to get into downtown which travels perpendicular along the Rio, and they are all walking along the fence line towards downtown like it's a Sunday stroll. Once there they are free to go anywhere they want since the BP are overrun and all holding facilities are full to the brim.