Upon remembering an old lesson I had in the boy scouts; I think the judge erred in his ruling. Instead of taking this on as a safety issue there is another law that covers this. United States Code Title 4 Chapter 1 - The Flag. More importantly
"Section 8. Respect for flag
d. The flag should never be used as wearing apparel, bedding, or drapery. It should never be festooned, drawn back, nor up, in folds, but always allowed to fall free. Bunting of blue, white, and red, always arranged with the blue above, the white in the middle, and the red below, should be used for covering a speaker's desk, draping the front of the platform, and for decoration in general."
So in reality people who are wearing clothing with the flag on it are actually violating US Code, believe it or not. So realistically they should have gone in with a flag bearer, piper and a drummer to make their point legally. The whole safety issue is a bunch of politcal correctness (PC) malarkey. Had I been one of the parents there, I would have gone after the Principal's job for not having a safe school for my kids. I mean if one shirt can cause open riots they must not be able to safety teach my child in an enclosed classroom. Perhaps the students should ask for permission to reenact the Mexican - American War to which California was also a key player in.
So in a nutshell the boys got sent home for some PC BS. They violated the US Code for displaying the flag as apparel. Finally, their parents went the wrong way with the lawsuit. If the school head administrator fears for their safety; there must be something inherently wrong with this school.
Anyways keep this in mind when you see Old Glory as bed sheets and take the time to tell the store owner that he is violating not only US Code but degrading the Flag itself.