I was at event where someone made a portal thing kind of like this but not stretchy. Someone who was definitely intoxicated on likely multiple substances did try to run through it. It had been mounted to the bottom of a utility pole. Fortunately they didn't have any serious injuries. Just some scrapes and bruises. And the artist that built it just said, "yeah, I should have seen that coming."
My mate made this. Awesome to see his work go viral. Its interactive with an ipad controller with heaps of mapped parameters to affect the kaleidoscope - https://tricktronix.com/
Someone tripping is going to try and run through the portal.