Sorry if this has been asked before. In the several years that I have owned a pop-up, I have always unzipped the bunkends from the sidewalls before closing up. Recently I was at a friends house and we were closing up a trailer and I went to unzip them when he said that he has never unzipped it. It seems to be one of those small time-saving things, but now I am questioning it... and I don't know why. What do you do?