If your valuable intellectual property is being so poorly protected, it certainly would be prudent to not contribute to the catalog.
The problem @palmercr has so generously exposed is a design flaw, not a hack.
In fact, as it stands now, obtaining the source SVG does not require any hacking at all. It is automatically stored on your computer without you doing anything but preparing to print the file. Your browser will cache a copy of the file locally on your hard drive.
I suspect that GF’s developers will have a solution in place to prevent this prior to allowing people to submit their items.