I like your solution.
I had an idea for a portable screen made from PVC pipes which could be folded down packed away quickly. Being PVC it'd be very light and could easily be transported to a dark site where it could be useful not so much for blocking light but for shielding against light winds as well as providing some privacy from any stalkers or puppy love teenagers. I won't hijack this thread with a picture but maybe I'll post in a new one another time.