This is just another nail in the film coffin. It's an unbelievably bad idea.
1) Velvia 100 is still in production, and will remain so if we support it. Advocating retention of Velvia 50 splits the market.
2) Such a petition undermines the decisions of the managers at Fuji who selected which films to retain and which to drop.
This is extremely bad for the future of film in general, as senior management may question the validity of the decisions.