If you use an experience plugin or skills plugin and you are in a team, Player one can lay the thatch, and player 2 can /up over and over to gain free experience or skills points without any materials cost all they have to do is wait for the 60 second or whatever you have the cooldown set at.

"Use Teams": false,
    "Use Clans": true,
    "Use Friends": true,

Yea I was hoping there was a solution that involved not switching it off for teams. No big deal.

In the plugin, find and delete it, but other plugins will not prevent players from upgrading buildings

                if (Interface.CallHook("OnStructureUpgrade", buildingBlock, player, targetGrade) != null)
                {
                    return false;
                }