There are probably thousands of people doing this but we just stumbled on the practice last week. On a theatre run you always need to have extra batteries around. One of the hallmarks of a good tech is to be able to grab a pack from a panicked actor, dump a bad set of batteries, and get the new ones in (the right way) with one hand in the dark.
Things just got slightly easier. Some manufacturers have made it so you don't have to figure out which battery goes which way by having them both inserted in the same orientation. But whatever the setup, taping two AA batteries together will let you lock and load quicker than a Marine drill sargent. It also keeps them from rolling off the prop table and getting lost.
Many thanks to our own John Baiocco, otherwise known by his stage name "Chachi" for this one.