Check6
True what you say, neither medium is 100% proof against malicious acts. There are I feel more means of establishing credibility via radio than 'phone. (Put yourself in a controller's position and I'm sure you'll figure them out - assuming of course you're not one). I'm sure that SAT 'Phones will eventually become the norm for voice comms outwith VHF cover and any question of 'security/integrity' will be addressed.
Rgds
T3