I know many people might "hate me" for suggesting this - but you might want to concider having serial checks on your download page for your service release packages. At least this will limit the amount of warez people getting access to the updates. This has worked well for Rhino 3d and Vue 4 helping "limit" the amount of people downloading updates for use on illegal versions, Not hating you at all because it's a perfectly reasonable suggestion but you're operating under the misapprehension that it makes a difference. It doesn't. Only in the short term and for casual use. All the updates for all software, serial checked, member checked, paid or otherwise are available if you know where and how to look, and let's face it there's no secret about where and how. :( It would prevent immediate distribution but it won't prevent it longer than a few days unfortunately.