Wouldn't seating all of the unvaccinated fans together be worse? It just means all of the people most likely to spread it are going to spread it more effectively. Unless the logic is that at least they're only spread it to other irresponsible people (which is a bit unfair on the people who can't have the vaccine for whatever reason).
Anyway, I can't believe the government has missed this opportunity. Spend a few billion on a specific biometric vaccine passport. That way everyone gets a shiny new card, and their mates get another juicy government contract. Win-win.