In the pilot-episode (S01E01) of "Designated Survivor"; just after the explosion, Tom Kirkman's Secret Service agent tells him to get off the phone immediately and demands he hands over his "Government issue Black-Berry". The phone of his wife Alex is taken right out of her hand, and she's asked if she got any other "electronic devices".
Why was this done?
Of course, I can make several educated guesses as to why - not secure communication, ability to track their location (as was later done to the Kirkmans son), the possibility of using it for surveillance (bugging sound, maybe even picture), it could've been tampered with prior - or simply to keep them incommunicado for some reason (not to get false(?) information, not give-up his location or status as DS)... Are there other reasons? What would the main reason be?
Is this some standard procedure (well, "planned" is perhaps a better fit) if something like this should happen? Or was this more the agent showing initiative (or being a bit paranoid)?