I'll add a question to the sentence I bolded. If I make a transaction on the newly created fork-chain, wouldn't this be a legitimate transaction on the bitcoin chain as well? Meaning if someone relays transactions between chains you can't really spend coins from one chain only. Is there a good way to fork the chain without this happening?
I'm just sort of guesstimating (this not being a tech thread), but it seems to me that the best way to do this would be to manipulate the address format in backward-ish compatible way such that a spend would be invalid on fork and honored on another.
Let's say that the 'real' Bitcoin is called fork-A. In the case that a person wanted pre-fork coins to be spendable on fork-B, just modify the software such that it would accept both pre-fork keys and a special modification of keys which 'real' Bitcoin does not allow. Just generate new non-realbitcoin-legal keys if you don't want transactions to be able to be replayed on the 'real' fork-A. Should be pretty easy I would think.
Interestingly, transactions from the 'real' Bitcoin could be re-played in the 'B' chain. This would be an easy way to create even more 'deflation' or 'distribution' (or 'theft') or whatever.
Of course there would be nothing to stop 'real' Bitcoin from eventually making 'bitcoin-b' keys legal as well. But once the blockchians diverge even a little it would probably result in nothing but a giant mess.
As long as 'real' Bitcoin remains vaguely competitive on an operational level, my sense is that it would have nothing to 'fear' from out-of-band sister efforts of the nature described above.