If authorities started blocking the websites bitcoin.org and sourceforge.net/projects/bitcoin/ they could actually be doing the bitcoin community a favor!
A dozen alternative sources for the bitcoin client would spring up. Other conventional websites, .onion sites, .i2p sites, torrents, emule, usenet binaries, usb sticks hidden in geocaches, etc. The bitcoin community can be pretty evangelical, especially when provoked. Shutting down one source at a time would then become a game of whac-a-mole for the authorities, with each major shut down generating free publicity for bitcoin.
It would remove the only single point of failure that remains in this project.
At worst, this would cause the whole bitcoin project to fork into several parallel currencies with independent chains and slightly different clients/rules. But I see that as an advantage because it would mean even more resilience and redundance. Exchanging Bitcoin for Bytecoin is much easier than for USD or EUR; the overhead would almost be as low as for an internal Bitcoin transaction and the exchange rates would reflect the desirability of each Bitcoin fork.
Forks make us weaker. If the combined network has 4000Mhash/sec an attacker needs to match that amount. If it splits in half an attacker can doublespend on both networks with only 2000Mhash.
Obviously putting the code out on many sites is only a positive.
