Honest coordinators issue temporary bans to non-signer inputs as a DoS protection measure, so a convincing Sybil attacker would have to do the same.
So what do I do? Do I have to get myself banned 10 times, which is also a big waste of time on my end particularly if time is a very important resource and I am a Target, while trying to find out if the Attacker is quitting due to Mining Fee burns?
If somebody is so keen on trying to attack a Target, then may be safe to assume the Target is likely very important and therefore the Funding could be huge. And I imagine having a Million Dollars funding to spend on a Decoy Coordinator burning Mining Fees in an attempt of the successful Attack is not too extraordinary either.