Taco Bell wants to return the phrase "Taco Tuesday" to the people

[silenus]

I raised this question here 5 years ago.

Trademark question - "Taco Tuesday"

Thrillist article Short version - Taco John’s, a Mid-West chain, has trademarked the term “Taco Tuesday.” They periodically send out C&D letters to other restaurants using the phrase. But there is plenty of evidence that the phrase was in general use long before Taco John’s was even founded. If TJ’s sent a letter to Baker’s, for example, could Baker’s just respond with “FOAD?” Can any law types knowledgeable in trademark law bring me up to speed?