This is just a random thought. Remember back to the 70s and 80s. If someone from ABC's Three's Company would be the celebrity on NBC's Password Plus, they would say "Three's Company air Tuesday Nights on another network." They weren't allowed to say ABC.

Over the summer, I was alone one day and Alyssa Milano from Mistresses guest starred on The Talk. During the commercials, CBS was doing constant ads for Under The Dome (Mistresses time slot competition).

Julie Chen said "Watch Mistresses Monday night at 10 on ABC". When did this rule change or is Julie able to get by with this because she is the bosses wife.

Just wondering

I'm not sure it was ever an official rule, probably just a policy they had back in the era when you only had a few channels to pick from. Now with so many channels it makes no sense not to say where a show would air.