Another consideration: climbing out of the saddle can put more stress on the folding/extra long parts of a folder, particularly when one's technique isn't good. Even while seated, new riders often 'haul back' on the handlebars when trying to power up a hill in a higher gear. When standing, however, I've seen some riders throw a lot of weight onto their bars -- forwards and backwards and side to side -- not great for a long, folding handle-bar post.