I know charging for ambulance services is not really a great idea, since it puts genuinely ill people off, but maybe this is a case where it would work. I believe the fire brigade have a policy with public buildings, that if a fire alarm is set off accidentally - repeatedly - then they charge a fee of about £100 I think. Maybe you could have a similar arrangement with bus companies. I somehow doubt that just asking execs to behave responsibly is going to work! Call me cynical!