OF course they take the bolts out.
Been doing it for a very long time.
There is no need to have an operable weapon in a parade- plain and simple. This is prudent firearm safety. Forget an intentional shooting - accidents happen - no need to take a chance.
If they could - the Secret Service would probably want the local cops disarmed too.
Let's not forget - it was a Marine that took out JFK - they have reason to be nervous - lol.