How come I'm not allowed to simulate hijackings?

This stuff tends to get the attention of homeland security. (For obvious reasons). Feel free to simulate emergencies (engine out situations, for example). Just not the illegal stuff.  Remember, all interactions with ATC run through multiple third-party AI services, and such use is a violation of their terms of services. (And ours).  Accounts of people who do this are automatically terminated, will not be re-enabled, and will not receive a refund.