As with most bands headlining a multi act gig or festival. The headlining bands lighting rig is hung in place and used for the event. It's the only way it can be in place for the evenings performance.
In such cases. The rig won't be used to it's full potential until the headliners show.
"...Roberta Medina continues by saying that Queen were very generous because
they gave the orginizers and the other artists the full access to their
lighning rig throughout the festival. They gave technical support that
was unique because the organizers weren't used to deal with the
magnitude of this festival. She says Queen were very generous, because
without Queen's support, the story wouldn't be the same, and she isn't
sure if they could have made Rock in Rio to begin with."