Is post-processing allowed, for example? If yes, everything including light spikes could be claimed to be artificially added, not resulting from using different equipment. If pictures are required to be straight from the camera—well, there still are inevitable pre-production and (more importantly) RAW conversion steps.
You raise valid points, but taking a photo with a professional DSLR camera instead of the phone camera you are advertising goes way beyond post-processing.
> Well, there still are inevitable pre-production and (more importantly) RAW conversion steps.
Sure, but there is a standard procedure to get a photo out of your camera and onto your Facebook page, and that's pretty much the standard amount of processing necessary. I'm more interested to see what the photo would look like if I made it with their camera, than what a professional photographer with a DSLR and a Photoshop license can do with it.
Kudos to Apple for using real pictures, but this also made me realize how I hope phone cameras become much better and soon, because that pictures looks quite blurry to me. But at least they are showing people exactly what they can buy, instead of some fake or heavily retouched image that won't be reproduced in real life by 99.9% of the iPhone users.
I've heard that ‘big’ camera makes like Canon or Nikon regularly advertise their products using photos made with completely different equipment. It would be more surprising if Nokia used actual photos made with Lumia in promotion materials, I guess.
 http://www.kenrockwell.com/nikon/d3/h3d-1.htm: “For those of us in the press (Ken), we laughed when we looked at the EXIF data of Nikon's PR photos of the D3. They were shot in a studio, so of course Nikon had them shot with an appropriate camera: a $30,000 Phase One P45 back.” Anecdotal evidence, but I'm unable to find another source, so take it with a grain of salt.
Let's be careful about what we're talking about here. If the pictures are of the actual camera and are about showing the physical product then they're no doubt often shot in a studio with a proper studio camera. That's (probably) what Ken is talking about and there is nothing underhand about that.
If on the other hand the pictures are about showing what kind of results the camera can produce then I very much doubt they'd risk faking it by using a different camera.
Rockwell is a noted self-publicist with a politician's reputation for truth and accuracy. Nikon can take their PR shots with whatever is best, should P&S publicity shots be taken with that P&S model? Of course not. If on the other they take photos with professional equipment and claim or imply that it was taken with a mobile phone then that is deceitful.