One instance of this I've seen recently was a few seasons back where Air Force had recruited a local 5 star away completely away from the SIM and was the only school being considered at the 5pm cycle, decided he would try to redshirt him just prior to signings

... well let's just say when the 8pm cycle came, Air Force got dropped from consideration and the kid instantly signed with the SIM at 8:01pm (didn't give anyone else the option to recruit him). Totally makes sense given what happened though since I doubt anyone else had also put any effort into the recruit. Air Force never got the chance to recind the redshirt
