It isn't much of a "tourist trap" per-say BUT there are a lot of tourists that gather here.
Keep the equation in mind: lots of tourists=pick pockets delight
Be sure to keep an eye or hand on your valuables.
I've never had anything happen to me in the Marienplatz but that doesn't mean it couldn't happen.
Marienplatz is certainly a tourist magnet, sometimes to the point that it becomes very congested and a little annoying. You're likely to hear many languages spoken here and it would be a miracle if you could cross the square without hearing a camera shutter flutter.
No traps here, just another good picture (I hope) from Marienplatz to show.
This town is absolutely not to miss during christmas time. There is a wonderful atmosphere everywhere, people is peaceful wandering around ofr gifts or just only to enjoy. It is rather cold but, ok, it is still Germany during winter!
It's basically the big pedestrian zone. There are tons of shops, cafes, and other things to bide your time with. It is also home to the Rathaus, New Town Hall, and a way to get to the Hofbrauhaus.
Unique Suggestions: At least shop around before settling on buying anything. There are probably two dozen stores selling the exact same thing, so compare before spending.
Fun Alternatives: If you want to bargain shop then I would suggest getting off of Marienplatz. On the other hand, there are some nifty things about it and I wouldn't reccommend avoiding it all together. It is a very interesting street and not a bad way to spend an afternoon.
There are only a few tourist traps in Munich, especially in Downtown Munich!
NEVER got to a Bavarian restaurant nearby Marienplatz! All you´ll get is bad food for expensive prices! You´ll have to pay up to 20,- EUR for a regular lunch or dinner - without drinks!
As in every tourist city, near the main attractions, there are many tourist traps: pay attention to the rickshaw for tourists: they are incredible expensive!