Polar Bear Scene??!! (Spoilers)

The bear in the movie is fake for two practical reasons: first, the whole picture was made for a tiny budget, and polar bears are expensive; and second, polar bears are vicious and deadly wild animals that don't take easily to training. The polar bear in "Lost" was also obviously fake; it's not a plot point, as near as I can tell.

My reading of that sequence also goes two ways. On the one hand, it's clearly her fantasy, a moment of communing with the bear; throughout the picture she lives more or less completely within her head (I don't believe that she's mentally ill any more than I believe that the Red Balloon is an alien device, or that Bruce Willis's John McClane is an indestructible superman; she's a movie character, and so she lives mostly in a realm of urge and symbolism), and I saw this scene as a point where the audience shares her internal life without chains, even though she is shackled in reality.

On the other, I also think it was part of a whole Eve-in-the-Garden motif, where her innocence is total because she is living in a state of grace, childlike, without any notion of sin. The splash into the river feels a bit like a baptism (this point was contributed by the actress in a discussion of the film), and her ease in cavorting with a beast that doesn't kill her felt very Eve-like to me.

It was clear to me that she was not ever actually in the bear cage.

As for being released by the police, well yes, of course. The police do not generally throw people in the dungeon for looking through a someone's bag and not taking anything. The worst the charge could be is along the lines of disturbing the peace or trespass, and she would have been issued a ticket or given a court date and released.