Here's a link to a thought-provoking Shaffer-Gee paper on gaming and education (Before every child is left behind: epistemic games can solve the coming crisis in education).
It illustrates some of the advantages of RPGs for problem solving. In Madison 2200, players work as urban planners to redesign a downtown pedestrian mall. Games like these can provide a unique opportunity for individualized complex problem solving - but how the games are combined with conventional instruction will be crucial.
It's not hard to find examples of gaming students taking an unthinking approach to playing. Left to their own devices, many students could become lost, mimic the paying of others, or try to cheat. It's possible to not learn anything by playing games, but of course the same could be said for sitting in class.
Gaming and Education