Seems as if there’s not much that wasn’t said here, as none of the 85 people who read it decided to add a comment.

I’ve often wondered about such things. The American flag has special privileges, but no one has ever clearly defined what an American flag is, at least not to my thinking.
I’ve done a bit of research, believe me, and the only precise, legal description there is describes the flags to be used on military installations. If you go by that, then the fly (length) of the flag has to be 1.9 times the height, which means the 5-by-8 flags most people fly don’t qualify. Flags with eagles or Marine Corp emblems on them, outdoor flags with fringe, stars that are too big or too small…all those things make for a flag that is not a “legal” flag.
Politics aside, that’s why I don’t think we’ll ever see an amendment protecting the flag: no one can say what is or is not legally a flag, and that’s how it ought to be. The American flag, to me, is far more than can be described in measurements.