I've noticed that with ranges too. One range included a tag on the neutral terminal warning that if a three-wire circuit was used, an optional kit of parts was required (bond strap and a screw, I'm sure). I seriously doubt that any DIY or even appliance installer is going to bother. Despite the NEC's good intentions to support the manufacturer's marketing needs (see AFCI, tamper-resistant receptacles, weatherproof receptacles, etc.), it would seem that we now just have lots of dryers and ranges being connected with no form of frame ground whatsoever.
