Whilst I do not know about magnets on the 400 Series cameras specifically, the older R200 cased USB model - which is also a stereo camera - has a strong magnet on its rear, covered by a magnetic plate. The purpose is so the camera can be attached to surfaces such as monitors when the magnetic plate is removed. The magnet has no ill effects on the R200's operation.
Edit: I checked the 400 Series' data sheet document, and there is no mention of magnets at all. It would likely be listed in the document if it was a potential problem.
The R200 is still available at a discount price in Intel's online Click store, as it is a retired model and the stock is being cleared. It has greatly lesser capabilities than the 400 Series due to its age, but may be sufficient for simple monitoring applications.