If it has value in the game, it has value.

Regardless of whether or not it should be bannable, there must be consequences for bad behaviors. If there were a system for dealing with in game "crimes" other than reporting and getting the person banned, that would be one thing, but as it stands right now, there is no such system, so banning/suspending is currently the only way to get through to people that such things are not permitted.

In the anime Log Horizon, the council they set up dealt with crimes by locking criminals out of vital services. The game world also had a system in place to deal with players attacking players inside towns. The later is not a problem for this game, because there is no random pvp.

As far as I know, there hasn't been a huge scammer/thief problem in PG yet, and I sincerely hope that we never get to that point... but as I stated, unless they want to program in systems to deal with such things, I am a firm believer that it cannot be allowed to happen.