The worse case could be like ARBITAO, without prior knowledge I may join but then when I will be well aware of the scam and if I know that the account got hacked then I will leave the campaign without even informing the yahoo account owner (the hacked owner). And if I know for certain that yahoo account indeed is yahoo's then again I will inform him that I am going to leave his campaign after x amount of time or immediately. All depends on the situation.
So you'd join, advertise a scam, until someone else does the research you should be doing and points it out to you, at which point you'd leave after having advertised a scam for time X,
which could have been completely avoided if you had done your part before joining.