lukulus:
I think a list would avoid any confusion about who has made such an agreement or not and with whom. It would be unfortunate to play thinking we had such an agreement and the opponent saying no. Why ask before or during each game when a list would be so clear in advance?
Could such a list or link to the list be placed in such a location that it would be easily accessible both at the time it's made and into the future without doing some kind of search?