Originally Posted by backinthesaddle
For my curiosity, how can you tell just walking by the bike that the quick release is done improperly??
He saw that the curved concave side was facing outwards instead of inwards. In the open position, a lot of inexperienced people will just grab the lever and spin it around to tighten. Getting it as tight as possible by spinning it will result in only about 5-10% of the clamping force necessary. The proper procedure is to flip the lever laterally (instead of rotate) so that the concave side of the lever faces inwards.