At uni, decades ago, I was told that whenever a "mathematician" appeared up on the telly, it was to present their new idea of definining a new constant equal to 2pi...
Not the same now, of course, with shows like Numb3rs and Big Bang Theory, and a greater public awareness of the importance of numeracy.
I haven't heard of tau being considered pre-2001, though it must have happened here and there (I had the same idea independently, for example).