Depending on which store they will cut, tear or use scissors. It might also depend on who is helping you. Often they ask if you are ok with it. Tearing tends to be straighter. I prefer tearing but I know what you mean about it puckering a bit. When they tear make sure they tear pulling on side to the top and one to the bottom not side to side. when you use a hot iron with some water you can get it to shrink up to almost normal. I have had way more issues with scissor and rotary cut fabric with it being bowed and side ways.