“I wanted to put an upper/lower number on how many times we get asked about them,” said Jay Kornegay, executive vice president of racing and sports operations. Westgate Hotels. “Customers and even some of our own executives don’t know that we can’t do it. So we have to tell them and they’re like, ‘Oh, really? That’s too bad.'”

Some casinos have gotten creative. One has a bet called “Shake It Off,” which involves betting that a player will score a touchdown after fumbling the ball early in the game. But that’s as far as Las Vegas can go, since novelty bets are difficult to regulate. Some people, for example, will be informed of Swift’s plans in advance and could possibly place bets. Gambling sites that offer novelty belts tend to protect themselves against bad actors by setting low limits: between $100 and $250 in most cases.

“It’s more for fun,” Burns said. “We are not trying to make money from this. Honestly, we probably lose on a lot of these because it’s a real challenge for us to keep up with these things. I mean, I don’t know what color lipstick she’s going to use.”

Sports betting usually comes with a number of disclaimers. Do not bet where it is illegal. Don’t bet more than you can afford to lose. And, when it comes to Ms. Swift’s participation in Super Bowl LVIII, don’t bet without seeking expert opinion.

Want to spend a few bucks on Ms. Swift wearing a championship cap if Kansas City wins?

“It depends on how cute the hat is,” said Julia Bennet, president of the Taylor Swift Society at Eckerd College in St. Petersburg, Florida.

In a video conference last week, Ms. Bennet and three other club leaders (Kathryn Brown, Kinsey Perkins and Mara Lytle) offered some insights. No, they don’t think Ms. Swift will cry if the Chiefs lose. (“She’s tough,” Ms. Brown said.) Yes, they think she will be wearing red at the game. (“I’m thinking red T-shirts and black pants,” Ms. Bennet said.) And no, they do not believe there is a proposal in the field.