Is it entirely possible for a Breathing tube to be places into the opening of a Bag of Holding to create a flow of air thus eradicating the need for the 10 minute limitation. This would enable people to smuggle people into a town under their cloak.
This could create a MASS amount of damage when 3 people walk into a castle and dump an army of Kobolds under a sleep spell into an empty room with a sign making a promise of free munchies for the murder of anyone within sight. Or dumping a bunch of zombies onto an unsuspecting troll under the bridge. Or even better yet! Dumping 20 or 30 freshly tied up and gagged slave goblins in front of a lich to make an escape!!
This answer strongly depends on whether or not the opening to the bag cuts the air flow through the tube.