Sunderland have enforced bans upon a number of season-ticket holders following their refusal to sit down during matches at the Stadium of Light.
A photograph that has been circulating on Twitter shows one seat that the club have taped-up as part of their clamp-down on persistent standers.
Head of safety and security Paul Weir said: "We certainly don't wish to spoil the enjoyment of any supporters, we want a vibrant lively matchday atmosphere just as much as the fans do, but we also have legal obligations that we must be seen to be adhering to.
"We also have a duty of care to all of our supporters, including elderly and disabled fans who have contacted us very concerned that their enjoyment on a matchday is being compromised because people around them stand throughout the game.
"Naturally we want to ensure a safe, comfortable and enjoyable experience for everyone at the Stadium of Light and we'd ask supporters to listen to requests from stewards and help us to eradicate persistent standing for the sake of all fans."
Sunderland have claimed 12 points from a possible 27 in front of their own fans this season.