Re: Static Stretching...
I've experience more than a few 'warm ups' that left me colder and stiffer than when I got on the mat. Particulalry in cold weather.
I'd come into the dojo reasonably warm from biking a couple of kilometres to get there, and by the time the 'warm-up' was over I'd be stiff and cold and losing feeling in my feet from kneeling so much and maybe even starting to shiver if the weather was cold enough. Not a great way to then start a class.