This is a quote from the book "On Zero Confirmation Transactions" by Chris Pacia
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Up to this point we have been considering a network where all miners are using the “first-seen” policy or variations thereof. In such a network, we can
detect double spends and thus prevent almost all fraud attempts as long as our code is up-to-date with the various differences in miner policy.
But opponents of zero confirmations t
ransactions envision a dystopian world in which would-be fraudsters pay miners higher transaction fees to ignore the first-seen rule and include double spends in their blocks, essentially aiding...