Simple... just don’t protest by kneeling at the playing of the National Anthem and with our great flag. Do it at some other time! If on the field
then this law applies;
“Since 1998, federal law (viz., the United States Code 36 U.S.C. § 301) states that during a rendition of the national anthem, when the flag is displayed, all present including those in uniform should stand at attention; Non-military service individuals should face the flag with the right hand over the heart; Members of the Armed Forces and veterans who are present and not in uniform may render the military salute; military service persons not in uniform should remove their headdress with their right hand and hold the headdress at the left shoulder, the hand being over the heart; and Members of the Armed Forces and veterans who are in uniform should give the military salute at the first note of the anthem and maintain that position until the last note. The law further provides that when the flag is not displayed, all present should face toward the music and act in the same manner they would if the flag were displayed. Military law requires all vehicles on the installation to stop when the song is played and all individuals outside to stand at attention and face the direction of the music and either salute, in uniform, or place the right hand over the heart, if out of uniform. The law was amended in 2008, and since allows military veterans to salute out of uniform, as well.[68][69]“