My two cents about the spoils is that if you know something either about the map or about the other teams that they would not know, and that would influence your suggestion however much, you shouldn't say it.
That being said, I think there will always be a ton of gray area that will be hard to define. For example, when someone posts a dot map, clearly any suggestions will have an impact on other teams, but at the same time there are going to be cases where the lurker will recommend only on the basis of the screen shot posted (for example, I can't remember for which team, but I commented on a proposed dot map, saying move a city 1S, solely on the basis of what the screen shot looked like...I couldn't remember what terrain was where, or even what civ was in that direction).
That being said, I think there will always be a ton of gray area that will be hard to define. For example, when someone posts a dot map, clearly any suggestions will have an impact on other teams, but at the same time there are going to be cases where the lurker will recommend only on the basis of the screen shot posted (for example, I can't remember for which team, but I commented on a proposed dot map, saying move a city 1S, solely on the basis of what the screen shot looked like...I couldn't remember what terrain was where, or even what civ was in that direction).