When I worked at JoAnn's we were required to measure every full bolt of fabric sold to make sure the customer got what was paid for, wrapped or not. We did not have to measure special orders that were measured and sealed at corporate. That being said, my daughter was recently shorted on a special order of drapery fabric. The clerk insisted on measuring it and sure enough, it was short. They were able to make it up from stock. It should not have been shipped without measuring even if she ordered more than 20 yards. Somebody goofed, but the local store caught it.
Those five yard precuts at WalMart sure don't look like five yards, but I've never bought one to see. I was overcharged at WM recently. I bought multiple small amounts of a line for a specific pattern - the Misty Rose. It was cut correctly, but when I got home, I discovered every fraction was incorrect - every one in WM's favor. I don't know if th error was with the cutter or if the chart she looked at was incorrect.