Not true! I've about had it with my Pyrex brand can opener which is supposed to remove the lid of a can by breaking the seal instead of cutting the lid, leaving no sharp edges. The problem is, the tolerances are tight. Sometimes it works well, sometimes it doesn't. I just opened two identical cans of tomatoes, packed in the USA. The first worked perfectly — the lid was lifted free by the little magnet. The second was a little balky. Usually, it is merely necessary to grab the lid and pull it off, but depending on how close to being free the lid is, it requires more or less force to finish the job. So, while applying the greater force required in this instance to wrest the lid from the can's grip, I slipped and sliced my thumb open on a knife-sharp edge.
This is a minor, but not trivial, wound. It doesn't require a trip to urgent care, but one Band-Aid does not suffice to stanch the flow of blood. It takes three to close a cut on the pad of the thumb. If you favor can openers of this type, I suggest you use great care when the lid fails to come completely free easily, and keep your first aid kit supplied with plenty of suitable bandages.