So it's ok to attack other people's monsters so they can't get drops? Knowing the issues that have happened with previous tournaments (people making accounts to pk others just to let their main have spots in wildy in King of the Skill, clans locking down areas to prevent people from necessary progress such as locking down shilo village quest I'm DMM) I wouldn't be surprised if people made accounts just to tag and grief others.
We've already seen players hopping at bosses and popular training spots just to crash ironman players, it only takes one damage to invalidate all the damage the other person made, not a huge time commitment to get a free world.
As I've said, I dont believe this is an issue because then both players miss out and there aren't huge IRL prizes on the line like DMM. Especially because a most damage system makes boosting accounts so much easier which I'd say is a bigger problem.
We'll keep an eye on the problem and try to control it as best as we can with more worlds if need be or banning those intentionally grieving or harassing where video evidence is given.