That guild seems to be a hive of scum and villainy. Even if she hands over the bandits' treasure there, looking at the average adventurers present, they will probably just steal all of the stuff and deliver none to the original owners. Furthermore, why would she join such a shady organisation that's obviously hosting criminals? Those guys manning the tables look more evil than the highwaymen in the cave. I'm sure she could make money elsewhere. Any kind of merchant guilds could probably handle the treasures better. Maybe even the city officials, though that could be risky as well.