What is the etiquette on painting the backside of a fence?

They have the wrong etiquettecy themselves lol...when you build a fence the back side is always supposed to face your property...They built it backwords..they left the hard part for you to paint with all the braces and poles and cutting in..all they have to do is put cardboard at the bottom to keep gr off the wood and roll away..no brush work...But they chose to put it up , they cannot expect you to share any costs at all preserving it..next they will even want you to paint or stain it the color they want..instead of something that would fit your decor....Your budget may not be as freely as thiers..don't let them stress you and make you spend money that you haven't counted on using..if they want it done that bad..they should do it..