Hmm
Containment procedures i don't like.
Firstly, resetting that long a combination every half-hour is stupid - it'd take bloody long to crack, and since it makes it a problem to memorise, it creates a weak spot from where they get the numbers. Everyone of level-3 clearance having the code memorised, and it changing when clearance changes seems saner.
Also - apprehending those with half dollars makes sense only if it goes missing - i imagine there are snack machines in Foundation buildings and it'd be incredibly impractical to check all currency around. Never mind a thief sure as hell wouldn't be seen "handling" the item.
As for the item - Scrooge McDuck's coin? Not too impressed, but not bad enough to downvote, that is, if you make up a saner containment procedure