Can't remember the last time I've gone into a store to do service that it didn't take half an hour of moving dollies and carts to get to the electrical panels. Got one customer I do a lot of work for who insists on putting a China hutch in front of the panel, it doesn't move easily, and afraid of breaking some fancy porcelain everytime got to get into the panelboard. Or the tripping over mop and broom handles as well as boxes to get to the breakers. Tell them but it does no good, it's an all too convenient space for storage (for them).
AFA the dead panel (never serviced) but sounds as if there is a feeder going into it, remove the panel if they need storage, it just sets a bad precedence. But they will do whatever they will do, just don't condone it.