The characters frequently press buttons and use touchscreens and stuff even though they are robots who I'd expect to send such messages over radio. But this could be a deliberate worldbuilding choice if actual robots value their privacy more than we do.
It is a deliberate worldbuilding choice, but not specifically for privacy. (Though, I do value cybersecurity, and am pleasantly surprised that the game world follows suit!)
When I finally get to making the mini-game for robo-tea:2ndServing!, I'll try to make the actual reason more apparent. :P