» Fri Sep 21, 2012 6:02 pm
According to http://elderscrolls.wikia.com/wiki/Do_Not_Delete, the chests exist as a means to keep track of how much barter gold a merchant has. This is why you can pickpocket a merchant and his/her barter gold doesn't decrease. In addition, you're apparently able to drop these in dungeons and use them as ledges to reach areas that can't get gotten to normally since they float in place.
The idea put forward by SomeWelshGuy also seems to be pretty sound to me, so it could be for either purpose. Interestingly, there's a list of places where these DO NOT DELETE chests have been found on http://elderscrolls.wikia.com/wiki/Do_Not_Delete, and I'm not sure whether they all correspond to locations that have a ledger - though I know for a fact a lot of them do.