Writing as an adult Runescape player, it is difficult to determine how Jagex could have done more to prevent players like Anna getting into such trouble.
For years, under 13 year olds weren't officially allowed in the game. Many did play, but they could have their accounts banned, if they were outed as underage. These days, children are welcomed, but with restrictions.
Primarily their text interactions are limited to a wealth of pre-written comments. Everything required to play Runescape is in there, but nothing that eases free flowing conversation. They cannot type their own words.
Unfortunately, this mechanism only works if a player hasn't lied about their age, when (s)he set up their account. The onus is surely on the parents or guardians to oversee that part.
All players, underage or not, receive some protection from roaming player moderators. Identifiable by the silver crown in front of their names, these individuals have the authority to step in, if bullying is spotted.
Of course, sheer luck plays a part there. If no player moderator happens to be in the vicinity, then there is a 24/7 Community Support Team to contact. Their mission statement makes it clear that on-line child safety is within their remit:
The Community Safety Team works in conjunction with worldwide law enforcement organisations and child protection agencies on issues related to child safety, threats, cyberbullying and abuse. This includes conducting investigations into players who we feel may potentially pose a threat to the safety of others, and reporting any incidents which raise sufficient cause for concern.
On the rare occasions when the team is contacted by Law Enforcement or Child Protection agencies, the Community Safety Team assists with enquiries and provides relevant information where necessary. The Community Safety Team also works closely with other Player Support and Content Development teams to make our games safe for all. The team also helps to educate players on topics related to online safety.
Jagex Games Studio: Parent's Guide - Community Safety
Again, as a player, I can confirm that this education occurs. We've all ventured into the Stronghold of Security, where we answer questions about online safety in return for in-game rewards.
That's not nearly all. Sometimes the awareness campaigns are so blatant and intrusive, as to appear patronizing to adult players. But we suffer them. We know how important such messages are; and we are not necessarily the target audience.
This is merely the official support for children being bullied or worse. It doesn't account for the rest of the player base. That can be really ferocious, if something is being said that simply isn't right.
Just two days ago, I was in the Grand Exchange, a central hub which is busy at any time of the day and night. A player typed a racist comment into the chat, which was immediately addressed by several people present. For ten to fifteen minutes, the debate flashed back and forth. Reasoned, coherent rebuttals, interspersed with trollish responses.