One usage per round, only one die may be on this action space
(can only be used by one player once per round).
Use one die of any value.
Flip over a city bonus marker on any small city.
While the marker is flipped:
The ! city bonus action for that city is inactive.
Any player entering this city must stop there, end their movement
and place a trading post there if they haven't done so previously.
Any player leaving this city must pay 2 coins (to hire a local guide).
You cannot enter and leave this city during the same movement action.
You can enter and leave this city during the same turn
(example: use a completed contract movement bonus to enter the city
and then a travel action to leave the city).
Reset the city bonus marker after ! city bonuses are awarded in the next round.
I think dice are too valuable in this game to be used purely to affect other players in a negative way while providing no benefit to yourself.
Plus, the game is tight enough as it is without additional strain to get resources needed to travel or complete contracts.
Clearly this action is only negative - it does not give anything positive to the player who takes it. To me this sounds more like the kind of action that would be caused by an event card - if there were a stack of event cards to be turned up, one per round - rather than an action that a player would take with a die. A sandstorm is a random environmental event that affects anyone in its path; it is not caused by a person.
Dice actions are a precious commodity in this game. It seems counter to the spirit of the game to have an action that a player would take to simply set opponents back. The game provides enough challenges with the high cost of travel; direct confrontation seems unnecessary.
If you want a "take that" element in the game, this would work. But it's not something I look for in a game like this. It would fit better in a game like Lancaster - which is an excellent game, BTW.
It also seems to me to be too many things going on.
The bonus doesn't work, and you have to stop there, and you have to pay to leave etc.
I think the "thematic" element is cool, but not really mechanic.