Bar dartboard etiquette

I thought bar/pub dartboard etiquette, in places with one board you don't reserve or pay for, was you can't hog the board--if someone else wants to play you can finish your game but then you have to play them, and if they win they get the board for a game, but same rules then apply to them.
We were at a familiar bar the other night and ran into a couple who had friends coming in an hour and said we couldn't challenge for the board, and things got tense when my friend called bullshit. The guy said he had never heard of the rule.
Are there parts of the world with different ways of doing this?

This rule certainly is used for the pool table, never seen it used for darts

Some intelligent ladiezzz here

they gon be havin your baby?

baby