In a Telegraph newspaper article about Daniel Levy, Chairman of Tottenham Hotspur Football club, and run of poor results, it stated that "An increasing number of Spurs supporters are turning on Levy and there were claims on social media that fans had 'Levy Out' banners taken off them by club stewards at the game against Stoke City on Sunday. Anybody wishing to take a banner inside White Hart Lane must get the prior approval of the club for health and safety reasons."
The club does have a rule in place that requires all banners (not just those about an unpopular 'chairman'!) to be notified in advance and this is for fire safety reasons. Given the challenges of crowd management at football matches this is an entirely reasonable rule to have in place.