I'm a member of the QueLab makerspace and I was there when the solar balloon got away from us in a sudden gust of wind. If you didn't know what it was, it did look pretty weird. A giant black triangle hanging in the sky.
We *tried* to tell people it was a balloon, but some people *refused to believe us*. They told us we didnt' know what we were talking about, that we were lying, part of a cover up, etc. Fortunately we had plenty of pictures of it on the ground, as well as a smaller prototype version, and a tracking system on the balloon. Otherwise, this might have been declared a real UFO by some.