Related video above: Historic Packers game at Lambeau Field without fans in standsNFL coaches thumbed their collective — and exposed — noses at the NFL’s mask mandate in Week 2.The league responded with hefty fines of $100,000 per coach and $250,000 per club. The first three to get fined were Denver’s Vic Fangio, San Francisco’s Kyle Shanahan and Seattle’s Pete Carroll, according to a person with knowledge of the punishment who spoke to The Associated Press on condition of anonymity because the coaches were not identified. The punishment was meted out a week after the NFL reminded team personnel on the sidelines about the rules for wearing face coverings during the coronavirus pandemic, lest they put the fledgling season at risk. Troy Vincent, the NFL’s executive vice president of football operations, sent a memo to clubs last week cautioning coaching personnel to wear their masks at all times. In the memo, Vincent said failure to adhere to the protocols in place would lead to sanctions, according to quotes within the memo obtained by CNN from a league source.The memo came after several NFL coaches were seen not following league protocols for face coverings during the first NFL Sunday since the coronavirus pandemic.”We must remain vigilant and disciplined in following the processes and protocols put in place by not only the league, union and clubs, but also by state and local governments,” Vincent said in the memo. “The NFL-NFLPA Game Day Protocol, which reflects the advice of infectious disease experts, club medical staffs and local and state governmental regulations requires all individuals with bench area access (including coaches and members of the club medical staff) to wear face coverings at all times.”However, during Monday night’s game in Las Vegas, both Raiders head coach Jon Gruden and Saints head coach Sean Payton were seen without masks. Payton, in March, was the first NFL figure to publicly acknowledge he had tested positive for coronavirus.When asked about not wearing his mask in a post game interview, Gruden said he has previously had the virus and would accept the fine if it’s ordered.”I’m doing my best. I’ve had the virus. OK? I’m doing my best. I’m very sensitive about it,” Gruden said. “But I’m calling plays. I just want to communicate these situations. I apologize. And if I get fined, I will have to pay the fine. I’m very sensitive about all of that, and I apologize.”The scenes were similar Sunday with head coaches and assistants apparently finding it too hard to keep their faces covered as required under the league’s COVID-19 protocols with either a mask, gaiter or face shield. Players, who, like the coaches, are subject to daily COVID-19 tests, are exempt from the face covering requirements.CNN contributed to this report.