Years ago when I worked in live audio we had a similar setup. Zero tolerance for a performer's mic pack dying mid show because a low battery indicator wasn't calibrated right or someone incorrectly tracked how many hours a particular set had been used, so it was fresh-from-the-package alkaline AAs installed before every set, and a virtually unlimited supply of half-charged disposables to take home afterwards. Plenty would get reused for internal equipment checks and sound checks, but there were still more than enough to go around.

At the time (well over a decade ago) there was still lots of skepticism around recharagables and the extra process involved in dealing with them... but the tech has gotten lots better since, at that time even low-self-discharge was sort of hard to find. I'm sure much of the industry has moved over by now.