Why just for big games?
We want to make a fortress a place where away teams and fans come and feel unwelcome. We need to have things like this to show we are different to other teams. Flags, sirens, fireworks, a team of well trained eagles swooping down in the pattern of the badge. Go to any American sports game, they will show you how its done, mostly because the actual sport they have is total pony, but they know how to hype the crown and make an atmosphere like no one else. We would do well to emulate that.