The present overnight encampments are problematic both for the OWS movement and their host cities.
The free-form leadership style is wonderful (even considering the comment by Oscar Wilde "The problem with socialism is too many meetings." ) Still this form leaves them prey to any group of anarchists or so inclined troublemakers to put on "Occupy" t-shirts and go out and trash the neighborhood. This has already happened in Oakland. The tent cities can also attract petty ante criminals who use them as cover to do their own thing.
It is problematic for the cities too. What is to prevent a group of homeless people from setting up tents, staying there permanently, and announcing that they are using free speech to protest the city's housing policy. I know this touches on the much larger issue of homelessness and inequality ( back to OWS ). Still the city has a point. I know it is nice to romanticize poverty, but I grew up a in poor neighborhood and watched people make bad decisions that made life for themselves and those around them much worst than it had to be.
The whole issue comes down to class. If the campers had been poor rather than middle class, they probably would be languishing in jail with 10 year sentences for assaulting a policeman, and few would even notice.
Excuse my rant. I am wholly behind OWS, but I believe the camping out tactic is not sustainable.