Really need to discuss the rules before play starts. Everybody needs to be on the same page.This reminds me of a situation I had once. It was league, one of their team refereeing. My opponent scratched (leaving me an easy finish). League rules were that the referee should retrieve the cue ball from the gulley and put it back on the table, if the player does it, it's a foul. But by local convention and sense of sportsmanship, most people/teams didn't apply the rule.
I looked to the ref, gave him a few seconds to go get the CB if he wanted to (he stayed completely still, made no indication he was going to get the ball), then I went and got it myself. Obviously he called a foul and the other guy won the frame.
The lesson to me was if you're going to trust a stranger to be pragmatic / honest, sometimes you're going to be disappointed. At least explicitly ask the question, whether they'll allow whatever you're planning to do.
I used to play in some black pool rooms years ago. The rules were always changing as we played it seemed.
I didn't care about the rules as long as I know what they were. They played games you never heard of.
A popular one was 8 ball in Georgia.