I remember this came up a couple of years ago.   I even recall seeing an image of a 3d print though I can't recall if it was a commercial model or the modeler's own.   I would assume distributing the .obj or .3ds file they need to print it is against the license as that would mean the geometry could be extracted.

Here's a thread from back then discussing it.  http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3579032&ebot_calc_page#message_3579032