I snip the corners too and very seldom have a problem. Seems the cheaper fabrics will fray worse than the designer ones. If there is any fraying, I make sure I cut off the the fraying before putting in the dryer, and then cut a little bit bigger corner off. I also use cotton pillow covers that have zippers on them. No need for pins. I keep these covers solely for washing fabric. Had the covers around from when I had to cover my son's pillows due to allergies.