I think that it depends on the type of FSL design size and density. I wouldn't try with my large FSL doilies for sure, as they are very dense, but with small, less dense (more open) designs you could try on organza and light fabrics.
That may depend on the individual design and what fabric you plan to use it on. Many use FSL designs on organza etc, but a thicker fabric might cause problems as the design is meant to be solid enough to stand on it's own. Maybe you could try a small section of what you plan to use and see how it goes. I'd be interested to see how it works. What kind of project are you planning, if you'd like to tell us more?