Splitting a currency unit into two does not dilute the currency any more than moving the decimal point does.
In order to dilute you would need to create new units and issue them to someone other than existing holders.
Well mining does create new units, doesn't it? And instead of having +6mn coins, you then have +12mn due to parallel mining of +3600 coins on each fork.
Regarding existing holders, if you have your own keys you are relatively ok (minus the obvious destruction of USD value), but the situation with coins in online exchanges and wallets will be "problematic" if say an exchange with 500k BTCs, say 'ok my clients, now you have 500k BTCCs because we adopted this fork' (and
we are keeping 500k BTCs of the other fork for ourselves). It would be like stealing BTCs and exchanging them for Gavincoins.
People need to do a bank run in every exchange (maybe even online wallets too) well before we reach the point of the hard fork, to ensure that they have control of their BTCs.
Alex, what have you been smoking dear boy? I'd like some.
Exchanges would be in court for years, well the ones that didn't have their doors smashed in, if they tried a slight of hand like that