That would be hard if you live in the same house and use the same internet connection
In regards to account sharing and account selling:This all looks like it is normal for competitive players to gather warnings like candy and getting banned in the end. Why do some people always try to cross the line and not think for once how they behave?
This game uses moba-esque balancing approach with strong group-based niches for playable classes, while simultaneously having MMO approach of long leveling and gearing process to make said classes viable at high level of play
This essentially makes character sharing a nesessity if you want to play competitively but cant spend months leveling and gearing up multitude of different characters
This is a problem with game's design, not with players.