About the commercial issue: Not sure how Poser does it, but Daz Studio handles it through plugins through their store. It also handles the serial number setup as well. You can't bypass it as the program checks the Daz site for the serial number to verify it. Definitely more protection for the vendor.

I believe Carrara does it that way too if you sell it through Daz's store. However, I have seen plenty of third party plugins sold elsewhere that have their own software protection scheme. This would be doable if you didn't want to use Renderosity's store. Obviously it wouldn't get the exposure to the Poser community that Renderosity would provide, but it's still an option. As a third party store, you would have complete control over the security.