Well, American chair umpire Gregory Allensworth was recently accused of making this mistake in Cincinnati not once but twice.

And the umpire jumped into swift action. Greg Allensworth got down from his chair and raced over. He then got on his radio for Gerry Armstrong to request security intervened. He said: "Gerry ...

Reilly Opelka’s win over Cameron Norrie at the Dallas Open ended in controversial fashion and the American didn’t hold back in his criticism of chair umpire Greg Allensworth after the match.

"I can't just be a punching bag": Reilly Opelka sounds off on Greg Allensworth, lack of accountability ...