At most matches, there are two teams: the 'home team' (playing at their home ground) who play against the 'away team' (the team who have travelled - away from home- to play at their opponents' ground). The fans who travel along with the 'away team' are the 'supporters of the away team'. The club did not decide to reduce the number of tickets for their own supporters - they decided to reduce the tickets for the supporters of the teams who come to their stadium to play AGAINST their team. I hope that's clearer now.