There is a rule at airshows that prohibits all engine,props and rotors turning during a para-drop, until everyone of the paras is on the ground and `chutes secure.This is for a very good reason - I have seen a para, get off-course and get blown/sucked into a prop about 30 yrs ago.and it was a Mustang prop too. Fortunately the pilot saw what was about to happen and shut-down with no serious injuries .
I would suggest that one should stay well clear of the circuit ,and wait to be cleared in by the DZcontroller/Fiso/ somebody who is responsible/ as its going to be his neck in the noose and yours if you don`t. The a/f in question must have specific contol procedures in place for such operations.If not-stay away !!