Identify and ban is the only real deterrent. Stewards seem to just escort them back over the wall or fence to their area rather than heading to the gate. So yeah more and better stewarding for starters. Tbh we all generally know who are the likely culprits, what area of the ground they frequent so where security should be targeted, It's not the occasional attention seeker that runs across the pitch or the streaker we're talking about, its the same shower each time that think they are above the regulations 'cause they think they are essential to clubs. Without realising it they are as arrogant as club directors that sit in their ivory towers making decisions that these fans protest against.