Destroying the evidence.
Via Atlantic Wire:
The latest Occupy Wall Street encampment to fall to a city police force was in Denver overnight, where retreating protesters left cops a set of burning shelters to deal with as they made their way out of the camp. The shelters were a key element of that encampment’s wrangling with the city, which it sued for the right to remain in the downtown Civic Center. Denver’s pretty cold in the winter, obviously, so occupiers can’t survive without their shelters — and as you can see in the photo, those shelters were more substantial than regular camping tents. Because of the cold, Occupy Denver also employed warming fires, so unlike other sites, there was plenty of combustion already when the cops arrived. The Denver Post described the scene as police moved in on the relatively small group of about 40 protesters who first “Tebowed” and then sang “God Bless America” before making their scorched-tent retreat.