On some of the newer intamin freefalls, I know that it won't lock until it is pulled down to a certain position. The reason is quite obvious. I've never ridden an INTAMIN coaster before, but I can imagine what it would be like having a lapbar/OTSR that locks where ever it is. That would be awesome. Just don't pull it down too far, as it won't go back up.
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Georgia Cyclone-The Most A Coaster Can BEEEEEEEE.