Popcorn and paintball...
When people ask, "Why can't I bring my own paintballs to your field," our typical response is a question - "Do you bring your own popcorn to the movies?"
"Uhhhh, yeah. I do"
Some get it. Some don't.
Let's try some new ones:
Do you take your own oil to an oil change?
Do you bring your own bucket of balls to the driving range?
Do you bring your own drinks to a restaurant?
I've heard of people who keep their fast food drink cup and bring it with them for refills each time they visit.
Maybe I'm the one that doesn't get it!