I think one of the things that happens fairly often is people AI and then a very short time later send 'em out with the bull. They then assume if they calve to the AI date that it is an AI calf - despite the fact that a cow can calve 30 days on either side of her due date and still be "normal" (way outside the bell shaped curve but normal) - and the only time this is found out is when the animal is tested for one reason or another or has a calf that doesn't parentally verify...I think that is pretty common. I hope the deliberate deception is rare but I am not sure I believe it is rare...ps I think you are a "real cattle person" and an honest one ;D