Well they are indication, just not conclusive evidence, since they can be natural or faked (at a cost)
smooth in Bill Clinton mode.
They can also be an indication of deception to confuse when there are actually attacks ongoing, which was CfB's correct point.
Good thing we do not have any such confusion then!
It seems no one is interested in spending money to create confusion about attacks they aren't performing.
Obviously if block chain observers are using the presence of ephemeral forks (i.e. orphaned chains) which are outside the normal variance threshold window of orphaned chains, then attackers may be financially motivated to created ephemeral forks which are not attacks. How did you measure that an attack is an attack again

(you objectively can't!)
And don't tell me that they waste resources, because 1) the profitability or justification for hiding the attack may be sufficient to do so, 2) by doing so gradually they can raise the normal variance threshold (see #c below) thus forcing the system to require more confirmations or rely on less than confirmed probabilities, and even if not then 3) remember they may be able to charge those resources to collective, e.g. how you and I proved recently that the Chinese mining cartel (which control 67% of Bitcoin's hashrate) is lying (and thus we can assume there is some massive high-level corruption going on, possibly stealing Three Gorge's Dam electricity at no cost).
But lack of ephemeral forks is conclusive evidence of lack of an attack, subject to the (reasonable) conditions I stated above.
Wrong again. Example, Finney attack. Example, a double-spend that falls within the expected number of confirmations of normal orphan rate.
And censored transactions with ongoing 51% attack where there are no forks other than normal ones with the expected number of confirmations of normal orphan rate.
A Finley "attack" does not exist in the system as defined by the white paper, where PoW defines ordering (as opposed to mint timestamps as described in section 2). If people want to be dumb and rely on zero conf in Bitcoin, they are attacking themselves.
Several rebuttal points:
a) In fact most of the Bitcoin use relies on 0-confirmations. I've been selling BTC to rebit.ph lately, and the transactions confirm within seconds of the transaction being sent.
b) As I wrote before and you ignored, even relying on multiple confirmations may be within the normal variance window for orphaned chains.
c) An attacker can drive the normal variance window upwards as high as he wants to. This is the
analogous mistake/myopia you Monero guys made on your math for what you erroneously claimed fixed the block chain size
Tragedy of the Commons.
d) You ignored my point about ongoing 51% attack which is not an ephemeral fork but rather is the longest chain.
Sorry! There is no such objectivity in Satoshi's PoW other than the longest chain rule (LCR). Period!Eventually you will learn to respect the research I've done on this matter.