Great Western Trail and BARRAGE!

I Agree with ElTemblo, is an easy implementation that can be realized with some flaggable options like this:

O Allow automatic charge 1
O Allow automatic charge 2 (-1VP)
O Allow automatic charge 3 (-2VP)
O Don't charge

Players, only during their turn, can always flag/unflag every options that allow to charge something when they know that the charge can be usefull or not.
With this system you can allow only the charge 1 power, or charge 2 power but not 3, and so on, in every combinations. Only "don't charge" is the option that close every other possibilities.

Another implementation can be the number of times you can allow a charge. For example:

O Allow automatic charge 1 (All - 1 time - 2 times)
O Allow automatic charge 2 (-1VP) (All - 1 time - 2 times)
O Allow automatic charge 3 (-2VP) (All - 1 time - 2 times)
O Don't charge

"X times" is the number of players in that game.