A local referee David Thornhill (Norwich City fan and qualified referee, who also featured in Saturday’s match day programme) stepped in as fourth official when assistant referee Mark Jones was forced off through injury during the 1-1 draw between Norwich and Preston in the Sky Bet Championship on Saturday. This meant that the fourth official, Andy Davies, had to take his place, leaving the fourth official position uncovered.
And, I have been able to found another such incident where an elderly football fan replaces linesman, after Female referee gets injured In FC United Of Manchester Evo-Stik Northern Premier League game at Nantwich Town .
My question is,
Are there any more incidents where someone watching the game (qualified) has to replace fourth official or referee?
Note: Anyone can not replace referees or 4th official, that replacing person has to be qualified to do so. And this type of incidence is most likely to happen in lower leagues.