We took our twin boys to the FA Cup Final last year with no tickets, they were 6 the following week and are of average size for their age but we had no issue at all getting them in with us. We had front row top tier tickets so had lots of room for the four of us with just the two seats. Our boys have season tickets as of this season so will have their own seats from now on but we would take them again for this Final with no ticket, if we had to.