Not quite true. An FBO should not be used as a punishment (that would be dealt with by a fine/prison sentence).
The court must make a football banning order where an offender has been convicted of a relevant offence and it is satisfied that there are reasonable grounds to believe that making a banning order would help to prevent violence or disorder (Football Spectators Act 1989, s.14A)
The FBO should only be issued if there is a real threat of future disorder. Unfortunately magistrates do not usually follow this guidance and of course plod want as many handed out as possible. Keeps them in their cushy little number I guess.
Pitch encroachment as a one off offence with no other history of football related issues and no trouble with the club really shouldn’t equal a banning order but to get that outcome you really need to have proper representation in court. There are a few specialised football lawyers out there who know the correct rules and how to defend them. A bog standard solicitor from London Road probably won’t lead to the correct outcome.
https://www.theguardian.com/commentisfree/libertycentral/2010/jun/17/football-hooliganism-laws this is an old but good read about what can go on and still does to this day.