Clearly the problem here is that they aren't paying enough for survey missions. I mean sure the survey team aren't exactly blameless in this case, but this would have never become a problem if they weren't being compelled to perform low paying work. At least it seems that the people who are going to suffer due to this deserve it.
Yes, but the guild probably needs to manage costs, too. Many dungeons will turn out to be low leveled, which can only be confirmed after evaluation. And if they set the payment based on the dungeon level reported by the team, they give them an incentive to falsely evaluate them higher.
Killing the team who have total support and trust of the Guild of Adventurers is a very, VERY bad idea.
How though? They may be good at their job, but according to what topknot guy said, they've done this countless times before. Surely the guild would notice the worrying pattern that people who report problems with dungeons and seek to reevaluate them suddenly turn up heavily wounded shortly after.
(Also, you are the hero we needed for that spoiler
)