As the very wise
@Parteecia mentioned, they'd done it before to hold queue in '77 for Space Mountain.
But for Light Magic, after the first two weeks or so of utter disaster, they started opening up multiple backstage walking routes nightly and for hours at a time in multiple locations. To alleviate the disaster in the Small World Mall, they opened the gates next to the old Kodak kiosk in Fantasyland and sent everyone down the alley and through a tunnel that dumped us out on the Big Thunder Trail. And they also opened up the (rather smelly) alley from Coke Corner to the Emporium for hours every evening to help Main Street. It was utter chaos and very messy, but it at least prevented panic from breaking out in gridlocked crowds.
I think my favorite part of that summer was around late June, when they were getting desperate. To try and help with crowd flow, they decied to reverse the direction and order in which the show was designed to start; from Small World being the first show around 8:45 to Main Street being that first show and going in reverse. Then the stages rolled north to Small World for their second show, then back again to Main Street for the last two shows. Sometime after park closing, the stages were rolled home to the parade warehouse.
The problem is that the rolling stages were battery powered and using 1990's technology, so they had to charge up overnight and all day back in the parade warehouse behind Toontown. So to get them down behind Main Street to start the show, in early evening around 6:00 they'd roll all four massive stages silently down through the middle of the park and park them for preparations behind Main Street. They weren't designed to be seen in the daylight, much less without all the lights on and characters and pixies dancing on them, so you had these giant, hulking, creepy looking haunted forest stages rolling silently down the parade route in broad daylight.
After a few weeks of that, they got the Voice of Disneyland to boom out on repeat as the four stages rolled by...
"The large rolling stages you see passing by will be used in tonight's performance of Light Magic! Please check with a Disneyland Cast Member for showtimes and viewing areas! The large rolling stages you see passing by will be used in tonight's performance...."
It was a Chef's Kiss perfection for artistic and operational failure!
I wasn't there to see that, but remember hearing all about it on the Usenet forums. Seeing as how we didn't know what a drone was back then, it was described as just a remote controlled toy helicopter type thing dressed up with a Tinkerbell overlay. Like almost everything attached to Light Magic, it was an artistic and operational failure.