I didn't see this show. What was "the pot reference"?
Actually, I can probably guess. I have a bunch of friends who aren't Fraggle fans and who are always looking for drug symbolism in Fraggle Rock. It's actually pretty easy to find if you're looking for it -- pretty much anything is easy to find if you're looking for it.
They say that Mokey's song "The Joy" in _Invasion of the Toe Ticklers_ is pretty trippy (especially the "smell the grass" line).
And don't get them started on Cantus and his Magic Pipe.
-Sidebottom