Hi guys been one of the ghost viewers/user (without account) to have used this site especially for kings raid. And just giving my two cents worth in it, so i have this theory, where its about an invisible combat power. Each team that enters a certain dungeon is judged by combat power and combat potential, then deducted each character by its type. If dungeon combat power required exceeds team combat power then it is judged by combat potential deducted by character type, if combat potential is still below or is suspiciously below combat power required for the entered dungeon then ban is about 80/20.
So lets say each character t5 has a combat class of 1,000 using 4 characters will effectively give you 4,000 combat power and ch 6 hard mode lets say has 3,500 combat power required which easily checks out so with ir without mod youll be fine for ch6 hard mode but hell mode substantially jumps in difficulty which requires about 6,000. System then applies deduction from character type (less power if mobs have higher defense to either physical or magic) which effectively leads you to have 3,500 combat potential. If you raid a dungeon that requires 6000 combat power system sees its too much of a stretch for your team to do it, you immediately get banned in the next maintenance.
Again thats a theory its the most basic but effective system to weed out cheating players, thats why majority if games have combat classes and dungeon difficulty laid out for people to have an idea which they can take on and which they cant hope to win.