Frequency - no it wouldn't prevent them from stealing.  But, in the case of filing a suit for a registered copyright, the fact that they would have to deliberately export the obj mesh in order to upload it to SL in a court would go a long way toward proving intend to steal... and that can make a big difference in damages awarded.  I'm less worried though about obj meshes being stolen for my big pieces like the fountain I'm working on... its 40k verts, which would never work in SL. 

You are right, skin and clothing textures are far more likely to be stolen.  I saw a lot of stolen clothing at Utherverse when I was there.  You can report them, whether anything gets done about it is another question.  But that's another debate and beyond my original question.

Also, reading over Rosity's vendor requirements they specifically state the obj geometry must be stored separately in the geometry folder; so since I plan to sell here that settles it anyway.  But its been interesting and educational hearing some of the other reasons for doing so.