The House needs to rewrite the rules to include the SOTU speech (or any other presidential appearances) and to prohibit clothing with political slogans, banners, etc. of whatever the political persuasion. Otherwise it will turn into a event for political protest.
I can't understand why anyone would be so uncouth as to wear a slogan-bearing t-shirt to a formal event like that anyway. If I had been invited, I would have regarded it as the honor it is and arrive in the best outfit I own.