Here is our take on the situation.
IAW AR 600-8-2, paragraph 3-1, a flag prohibits the following:
- Appointment, reappointment, reenlistment or extension
- Reasignment (some exceptions apply)
- Appearance before a semi-centralized promotion board
- Promotions in grade, lateral appointments, and frocking
- Recommendations for, and receipt of, individual awards and decorations. (Exceptions per AR 600-8-22)
- Attendance at military schools. (Exceptions with approval of DCS, G-3/5/7)
- Unqualified resignation, retirement or discharge.
- Advance or excess leave (exception to policy may be granted by commanders IAW AR 600-8-10)
- Payment of enlistment bonus or selective reenlistment bonus.
- Assumption of command.
Training holidays have nothing to do with a flag. Training holidays are not a favorable personnel action.
Can they force a Soldier to work on a training holiday?
Sure, but have to be careful it won’t be considered as punishment. If the Soldier is facing UCMJ from what ever caused the flag.
May the Soldier work on a training holiday of their own accord?
Sure, but that would be on the choice of the Soldier, having nothing to do with being flagged.
Unless the Soldier is on extra duty from UCMJ action or normally scheduled on a duty roster, the best course of action is to let that Soldier have the day off with everyone else for the Training Holiday