What kind of valuables do you all keep in your daypack? Or is it not a good idea at all? I do have a money belt AND a neck pocket. But it would nice to put some documents/passport/tickets in the daypack.

What bad things could happen to a daypack?

On a side note, one way to make it harder for the pick pockets is to stuff a handkerchief ( a hanky?)/small cloth napkin crumpled into a ball on top of your wallet in your side pocket. Then one would need REALLY long fingers to get both out in one attempt.