"Just because the NFL sent out a letter does not mean they are not legal."

Norm, I would bet my last chip that your theory is nothing more than at best wishful thinking, and at worst rationalization.

THe NFL charges a lot of money to use the words "Super BOwl" in conjunction with any product. That's why a local radio station that's giving away a trip to the Super Bowl will still say "win a trip to the big pro football championship game." THat's why a lot of beer companies, or pizza chains, urge people to "enjoy it while you watch the big game." If you hear someone use the word Super Bowl, you can bet they paid through the nose for the rights.

Now do you think that Circus actually paid for the right to use the name, but the NFL sent them the letter anyway, and Circus decided to remove the chips from play after already shelling out a ton of cash for the rights to use the name?

Or is it more likely they never bought the rights to begin with?

Well the NFL certainly claims in their letter that Circus never paid for the right to use their trademark. And Circus didn't dispute it. If it looks like a counterfeit, and acts like a counterfeit, odds are your talking about a counterfeit.