In July, the Indianapolis Colts started sending out emails to fans encouraging them to “join the 12th Man” and buy tickets for the team’s games. There are eleven guys on the field, so “12th Man” is a catchy marketing ploy. See, fans? It’s like you’re part of the team!

But that marketing strategy has been trademarked by Texas A&M since 1990. The Colts, who A&M says have been repeatedly notified of this starting in 2006, apparently opted to disregard the legal trademark. In response, Texas A&M’s Chancellor John Sharp announced Thursday that the school filed suit. As ESPN reports:

“Texas A&M University is the Home of the 12th Man which has brought our fan base national renown,” school president Michael K. Young said in a statement. “We would prefer not to file lawsuits to protect our trademarks. However, when our intellectual property, especially the 12th Man mark which is so important to our students and former students, is used without our permission after repeated attempts to engage on the matter, we are left with no choice.”

Suing NFL teams over the use of “12th Man” is something of a cottage industry for the Aggies. In 2006, they settled a suit with the Seattle Seahawks out of court, resulting in a ten-year license to use the phrase (so long as they credit A&M when it’s invoked on radio broadcasts). And they’re not the only NFL franchise paying A&M for the right to call their fans “12th Man.” The Buffalo Bills pay a licensing fee to the university, though over recent years they’ve begun phasing out the usage of the term (its 12th Man Walk of Fame was renamed Tim Russert Plaza, in honor of the newscaster and lifelong Bills fan).

Trademark protection is an aggressive art—let the usage of a trademark go without legal challenge, and you can lose the right to it, which is probably why A&M targeted Charles “Chuckie” Sonntag last year, a double amputee and cancer survivor who earned $825 a month via Social Security, who was sued for his Bills fan site (Sonntag renamed his site in response to the suit.)

The use of 12th Man at A&M dates back nearly a century, so even though organizations like the Colts, Bills, and Seahawks have been using it for decades (the Seahawks retired jersey #12 in 1984), it’d be hard to argue that A&M doesn’t have a reasonable claim to having originated the phrase. That’s something that then-Seahawks CEO Tod Leiweke acknowledged when his organization settled a suit with the school back in 2006. “We absolutely respect their tradition,” Leiweke said. “I’ve learned a lot about it. Our entire organization has learned a lot about it. It’s pretty amazing how far back it goes.”

When it comes to the Colts lawsuit, the odds are that this is about tradition and trademark protection, but also probably about the opportunity to set up another sweet licensing deal with a wealthy NFL franchise—a lucrative side-gig for the school, even with its $11.1 billion endowment. Can’t blame ’em for getting the action where it’s good, and the Colts—who should be aware of the Seahawks lawsuit—really ought to have known better.