The bands melt off in warm climates. Also a not really DIR procedures that might hypothetically happen on a deep open circuit dive where dropping stages is that you might just use the clip on the second stage to clip off the hose when dropping the bottle to make the drop and the pickup faster. Again, not the best of procedures, but I have seen it done on deeper dives to speed things up. Most dives of this type are on breathers now so this isn't really applicable anymore.