"Creating" a left turn lane, a Houston thing?

You know what I'm talking about, when you're in the left turn lane and the car to the right of you turns on the left turn signal even though it's not an option in that lane. Is this a Houston thing, or is it something the newcomers have brought with them. I see it at least one once a week, usually on Westheimer or 6. Not surprising seeing as how those are arguably the two busiest streets in town. It drives me nuts! I have to fight the urge to honk.