According to the government, the full-body scanners that are standard at airports cost about $150,000 each. In the last decade or so, the Transportation Security Administration has invested over $100 million on the scanners, which are called "millimeter wave machines."
According to the National Registry of Exonerations' annual report, 151 people were exonerated in the U.S. in 2018. Together, they spent 1,639 years behind bars for crimes they didn't commit -- an average of about 11 years each.
The Confrontation Clause in the Sixth Amendment to the U.S. Constitution guarantees that, "in all criminal prosecutions, the accused shall enjoy the right...to be confronted with the witnesses against him." The courts have read this to mean that criminal defendants have the right to fully confront any evidence brought against them.
Last September, the then-attorney general announced that people with two or more convictions for sex offenses would be required to wear GPS monitors for life. He ordered 180 people to get fitted for GPS bracelets within 5 days.