I used to always wear over my shoulder my Bose headsets in their carrying case, and I'd have my rollaboard and a pocketbook - but on my last trip LAX T4's elite line escalator guard forbid me entrance until I put the headsets in my bag. The problem was I didn't have any space left so I had to take out my book in order to comply. Because you're allowed to carry a book in addition to your 2 carryon's but not wear your headsets around your shoulder.

(Just wanted to vent belatedly as it's in the same nutsy ballpark as what happened to the OP).