There could still be a way - unlikely, but not impossible; even fail safe, excellent as it is, will not be entirely fool-proof. Would probably require a deliberate act with malice aforethought, but sadly, as we know only too well these days, there are such people out there.
Fair enough - long time since I lived in the area, and wouldn't have had much experience of that one anyway. Too many level crossings along that line to be honest, but you can't really blame Network Rail (or BR as it then was) - spent millions on the road and bridge at Goring, only for locals...
West Worthing? If so, agree it's an absolute shocker - should be re-designed, some road traffic manoeuvres prohibited or something. Used to scare me rigid at times.