Drained antifreeze after winterizing; ok or not okay?

(1) Why drain the antifreeze? Leave it in so if any water should drip down to a low point, it will mix with the antifreeze that also collects at the low point.

(2) If you simply drain the antifreeze, you will leave a large amount of water still in the lines. This is why you can not simply drain the water and get all the water out. Thus you need antifreeze to replace (or mix) with the water that is left after draining.

In the spring you can drain the antifreeze and flush it with fresh water.