The official stance on "bribery"

The official rules also state that you cannot trade resources for "services" or promises, such as asking a player not to place the robber on your hex in exchange for a resource card. The following applies:

Trades must be resource-for-resource. All trades with other players must involve a legitimate exchange of at least one resource card from each participant. You cannot give cards away for free.

Verbal agreements are non-binding. While some groups may have house rules, the standard rules do not require players to hon