This doesn't just happen in the military. In a civilian job
Indeed. When I first arrived in Aberdeen to start with a large offshore operator, my relocation package included two months in a hotel, with £18 per diem (1989). When I said I’d arranged a rental I was told “no per diem”. Given the timing meant I wouldn’t be paid for 7 weeks, this was irksome. No logic could prevail so, sad to say, I checked in and never stayed in the hotel!