planned pump and dump is ethically acceptable?
My vote is YES
I think it is because everybody in one way or another try to manipulate the market as they want/wish to.
I think that in the cryptocurrency particular case, we are living in a grey area and what is ethical is essentially a subjective matter.
The pump organizer, just like Alice, have all the power. The organizer will choose what coin to pump ( depending on deep is their pocket but in general the organizer choose a dormant coin with very low trading volume),
.. so the organizer can buy it as cheap as possible before the pump event, the members (in general a telegraph app groups) then get the privileged information on which coin to pump. The group as a whole try to bump as much as possible then dump..
The group is aware what they got into to, they know the rules, etc.
BUT, most of my research on that subject is based on that academic paper.
Xu, Jiahua, and Benjamin Livshits. "The anatomy of a cryptocurrency pump-and-dump scheme." 28th {USENIX} Security Symposium ({USENIX} Security 19). 2019.