There are few opinions that you'll have occasion to employ in your everyday life, but this is one of them.
I always assumed it was the law that you have to use your turn signal whenever you're turning. Not so, apparently. At least according to the Court of Appeal. Resolving what is unquestionably an ambiguous statutory scheme, the Court holds that you only have to use your turn signal if other traffic will or might be affected by your turn, and if (but only if) that's the case, the turn signal needs to be on for 100 feet. As a result, if there's no traffic -- or no traffic that might be impacted by your turn -- you don't have to signal.
Good to know. Especially since I don't always use my turn signal. At least when I'm on a deserted road, I'm apparently safe from getting a ticket. Or, as here, a traffic stop so they can search my car.