Yes, that is tinfoil. No, I don't know why. But I'm sure it sounds lovely when it rains.
From the submitter:
My neighbor's contraption to keep the rain off you when going into the basement
...just use these tools, they said.
The age-old problem of finding a entertainment center on the side of the road strikes again. ~Not-So-Handy Andy
We tied it to the gutter on the other side. What could go wrong?