Convertible Vehicles
It’s widely known that President John F. Kennedy was assassinated while he was riding in a convertible. Due to this, any president after this incident is prohibited from sitting in a convertible vehicle. This only shows how dangerous it is to take on being the president of the US.
Secure Lines of Communication
One of the most crucial rules for any sitting president is that they only make calls from secure lines. This concerns private and personal calls. All incoming and outgoing calls for the US present are directed on a secure line for national security purposes.