Manx Grand Prix spectators are being warned – stay out of prohibited areas and stay out of trouble.
Clerk of the course, Neil Hanson, says if spectators stray from designated areas on the Mountain section of the course, practices will be stopped.
He says police may also be involved if people insist on watching from land marked off-limits because of the foot and mouth disease restrictions.
There are special areas for fans at the Gooseneck, the Bungalow, Keppel Gate, and Creg-ny-Baa.
But Mr Hanson has this warning (audio file attached):