Well it seems that you are not paying attention to the threads where you post on.
It seems you have not read what I wrote at all.
You can then taint one of your coins with coins which only exist on one of the forks. Let's say you get a few satoshis from block reward which occurred in a XT 8mb block (thus is not valid and does not exist on the 1mb chain).
Of course I know that. But how do you get those few satoshis?
Do you realize that 99.99% of the bitcoin holders will NOT know about that
bug feature of the protocol, or would not have the means or interest of exploiting it?
So how are you going to meet the 0.01% of users who know that, have got some coinbase satoshis from one of the branches, and are interested in trading single-branch bitcoins?
By the way, there is a minimum delay of 50 blocks (IIRC) before one can use coinbase coins, presumably to discourage this sort of hackery. On a branch with 25% of the mining power, that means at least 2 days. Wlll that branch survive that long?