Used in jails and prisons, to "check in" means to request a transfer into
protective custody.
Protective custody is an area within a prison or jail where security is tighter and officer presence is more pronounced. Protective custody is used mainly for rats, people with
mental illness and sex offenders.
Johnny
checked in the oher day after the guys in his
block found out what his charges were.
We told him last week that if he didn't check in, he would be sorry that he came to our
pod.