By not just MPs or Servicemen.
I recall the BBC journalists flying Cod War sorties making a note of the air mileage readings so they could claim mileage allowance.
Or of a film crew treated by their producer to a splendid open air cold buffet at the end of their shoot. To a man they all claimed for a meal as well because their TOS said they would get a hot lunch.
Or some military contractors who, as some of their number had volunteered for a team building weekend had asked or time off or cash in hand. That resulted in the team building being cancelled.