Martina McBride Fan Sues Casino and Security Guards

A Martina McBride concert got too rowdy for a California man who was roughed up and slammed to the concrete because he asked a security officer, "Are you an idiot?" ... according to a new lawsuit.

Michael Frydrych claims he and his wife were given complimentary tickets to the country singer's show at the Fantasy Springs Resort Casino. Once inside they moved up to sit with a friend who had better seats.

He says security came over and told them switching seats was prohibited. Frydrych says he then asked the guy -- in a "non-confrontational" way -- "May I ask you a question, are you an idiot?"

This pissed the guard off and, according to legal docs, 5 or 6 people swarmed in and grabbed Frydrych, zip tied his wrists and slammed him to the floor, causing his head to bleed.

Frydrych claims he was taken to a back room and interrogated ... then released and told it was his "lucky day."

The couple is suing the casino and wants hefty damages for Michael's injuries.