Rules are rules in Australia, even if you are a 20-time Grand Slam champion and one of the most recognisable people on the planet.
Roger Federer found that out this week when he was blocked access to a locker room at the Australian Open by a security guard who took his job very seriously.
A video circulating Twitter on Saturday showed the Swiss double defending champion stalled at the entrance for lacking his tournament accreditation.
WATCH: Roger Federer blocked by security from entering locker room. Video: Kind courtesy, Australian Open
Players, staff and media all wear identification badges on lanyards around their necks to access secure areas at Melbourne Park and even Federer was not allowed to breeze through without it.
There was no argument from the 37-year-old, however, and he stopped and waited patiently for his entourage to catch up with him.
He was finally let in when one of his team flashed the badge at the security guard, who nodded and smiled with the satisfaction of knowing he not been duped by a doppelganger.
Federer will continue his bid for a record seventh Australian Open title against Greece's Stefanos Tsitsipas in the fourth round on Sunday.