I used to work demo tables at a convention every year, as the company would pay for people's convention costs in exchange for 14 hours of volunteer work over the course of 5 days.
I decided after the first year that I would be volunteering my time overnight, instead of during the day. They ran after-hours games until 2am, and I usually stayed until 4am to run some more. We usually had about 100-150 people at 10pm, dwindling to about 20 by 4am.
By the end of the night, the temperatures inside are around 60, and nobody is sweating. It's fantastic.
I also decided to start getting dollar store deodorants, the little travel size ones, and leaving them out with some baby wipes with a sign that says something along the lines of "NO JUDGEMENT, EVERYONE FORGETS SOME TIMES, TAKE ONE" With a little picture of "wipe pits, apply deodorant" underneath.
Every year, about half the deodorants have been claimed.
Sure it's like $20 extra if I get things on sale, but it's a small price to pay for not having to smell Convention Stank.
And when my job is literally to walk around a big circle of 10-30 people, most of whom have been walking around since before noon in a hot dealer hall, walking through a wall of "Cool Breeze" is so much less unpleasant than BO.