Since in Bitcoin the policy is dictated by the majority of nodes (weighted against hash/sec), how would you guys react if a future majority were to decide that the current policy needed tweaking? I am thinking in particular of the policy that the total number of bitcoins is capped at 21 million.
Violating the inflation policy requires broader consent than 50% of the network. Essentially, a vast majority of Bitcoin-accepting vendors must agree to the change. See an
earlier discussion for more details.
How many of you would "fork" in such a scenario?
I think such a scenario is very unlikely, but I wouldn't personally "fork" on inflation grounds alone. Bitcoin inflation caps are just one of the many benefits Bitcoin provides.
On a related note, it seems that many of you see the builtin cap as good thing. What evidence would be required to change your mind about this?
The Bitcoin supply cap models real world commodities like gold and silver of which there is a fixed supply in the universe (nuclear trickery, notwithstanding). Comparing the performance of unlimited paper money and fixed supply commodity money over the last 1,000 years of history suggests that a currency with a fixed supply provides a more stable price level. For me to change my mind, I suppose someone would have to convince me that that interpretation of history is incorrect.