When a theater shows the King's anthem before a movie, foreigners may not know how to show respect for the King. In this case, if you see someone sitting down, or talking during the anthen, you should ask them to stand and not speak until it is over. The national anthem is played every day at 8a.m. and 6p.m.: if you see someone sitting or talking during the national anthem, you should remind them also. They will be angry that you corrected them: they will probably be happy that you explained how to be polite in this country