Every year, in Guernsey, there is a parade with bands playing, flags flying and everyone marching. There are contingents from the RM Band Plymouth, an RN Guardship, the old salts and younger family members, police, St John's Ambulance, Sea Cadets, Marine Cadets, in short about everyone. The parade commander is an RNVR 2.5 and NO ONE practises before hand. True some have been doing it for 30 or more years, but it goes without a hitch.
As related above, there is a case where you can go too far.