People managed to attend games for decades without big bags and rucksacks, even when they were hitchhiking to European games.
No real sympathy with the increasing number of child like people surgically attached to their rucksacks, like a security blanket.
Obviously different if it's for medical stuff.
Otherwise though, they'll survive for two hours without it and it'll make for a better experience for everyone around them. And that's before you consider the security issues and delays such bags cause at the entrance.