I have always only blown out the lines. I do leave the air hooked up for at least ten minutes. I also make sure I open all the drain lines while this is going on. I have never had a problem. When our son played college baseball I would have to blow out the lines after every trip so I did do it frequently although late February and March are not the coldest months but still would get below freezing for extended periods of time. Better that watching a baseball game in snow. However, everyone seems to have a strong opinion on this topic.
