How big of an advantage is this really?
I get if it's on a diamond table with tight pockets. If it's on a valley barbox with league pockets, the effect seems negligible (no clue though). Like you'll get skids, but you'll both skids. Shouldn't it even out? Won't their balls hang up just as much? If you clean the cueball before you shoot (if you have ball in hand), or before you break and run, technically wouldn't that favour you because they will be playing with a dirty cue ball more often.
I think the biggest advantage they'd have is when the ball skids for either of you, they'll be less upset. Sure it's slimy, but excluding how it effects you mentally. It seems not very effective.
I'd have to know more about both people's skill levels, the equipment, the format etc. Unless there's a specific way to play that they've practiced to make the ball go without sticking, or to skid less, it doesn't seem like a big deal. But, I've never been in that situation, so I don't know.
I think you should bring a towel and some talc of your own. Clean the ball before you shoot, and not even remotely subtely roll it around in a mountain of talc before you hand them a powdered donut. Or just go full chaos mode and put powdered talc everywhere. Play "It's a winter wonderland" on your phone. I wanna see snow angels and cueball trails. See if your league operator still wants to allow talc in his room after it looks like a scene from Scarface.
No one should have talc. Get a glove or wash your hands. Ruin it for everyone, that stuff is cancer.
