The first thing you could do is agree not to charter to politicians who don't endorse action.
Sunfish, do you really think for one minute that operators and or pilots would be so united? As soon as one operator refused a charter request, half a dozen would jump in and offer to do the same flight for a fraction of the cost.
It is akin to a CPL standing up to an employer for safety, pay or any other reason. No problem, half a dozen behind you mate ready to do it and keep their mouths shut.