To be frank, I was shocked when I first signed up at the "big six" that they accepted images of cellphones and other easily identifiable electronics.

Even without the names/logos, all modern electronics still have design patents and the companies haved copyrighted of the "look", aka the basic shapes, of the electronics. It's all about weighting the cost of litigation/judgments versus the profits they get from selling the images. That's why most of them won't touch photos of ipods with a ten foot pole, apple is just too litigious to make it worth it. There's no difference between ipods and the unique modern phones that you see in terms of legal protection. The only difference is that Apple is more likely to sue than Nokia (at least in their minds).

As a photographer, I would never upload a photo of modern electronics because of cost benieft analysis. I'd rather upload a photo of some not widely known artist's painting (a clear copyright violation) rather than upload a photo of the Razor phone (not so clear cut violation). Do the math. A simple (not completely accurate or complete) expected value (EV) calculation. Is the likely profit from the photo greater than the cost of litigation times the probability of being discovered and sued.

For artist's painting:
profit from photo: low to medium (1-25)
chance of being discovered and sued: almost nil
cost of the law suit: 3 to 5 digits

For ipod:
profit from photo: medium to high (25+)
chance of discovery and being sued: low-med
cost of law suit: 6+ digits

If I owned a stock agency I'd have the same rule as 123RF. The risk is greater than the reward, in my opinion. You should also note that the photographer is the one on the hook for the litigation costs as most if not all microstock agencies. So 123rf is also taking into consideration the possiblity that the photographer wouldn't be able to cover the costs of litigation.