Granting GB is always free, right?
Apart from demanding a court action if you haven't got a previous diplomacy deal, yes.
This would be a change from the action description, I believe.
Offer TributeYou transfer the agreed amount of GBs to a recipient.
Type: Free – You can perform any number of free actions per turn.Cost: No base cost; but 0,1 or more GBs to be given as tribute.
Check: Automatic.
Failure: There is no special penalty for failing to take this action, except the wrath of the recipient.
Note: Tribute appears as income (either under ‘extra income’ or ‘vassalage’) in the next P&H, and is thus available only from the next turn.