According to an ancient military axiom, “Without intelligence, one is vulnerable; without security, one is defenseless.” U.S. cryptologists had a long and difficult mission trying to deny information to the enemy from its own and South Vietnamese communications!!
No doubt COMSEC was a challenge. I remember "the big eye in the sky" coming up on guard warning various pilots they were violating various rules. Admittedly, when the stuff hit the fan and everyone was just trying to stay in the air, things may have gotten a bit loose and unprofessional.