You're right. I didn't bury mine at all. I laid it on the ground and used weed mat staples to hold it down. But, mine will eventually grow over with grass, don't know if that makes a difference.The apron doesn't really have to be deep, it just needs to extend out so diggers run into it, then cover it. IMO regular welded wire fencing would work for the apron. You're just discouraging diggers.
If the floor is level, you may be able to do without. Just check daily that diggers haven't been testing it.