From The American Conservative:

However, there are other, far less expensive options for immigration enforcement that have proven to be extremely effective, says Lars Trautman from the center-right R Street Institute. These include ankle-bracelet monitoring and access to legal representation.

“In a lot of these cases, especially with asylum seekers, there’s no need to detain them at all in the first place. In previous administrations, they were released with bracelets to ensure their return to immigration proceedings. A lot of the growth in these detainments really boils down to heavy-handed policies that Trump has enacted,” says Trautman.