They definitely need warrants, but 99% of the time, people/businesses voluntarily hand it over. In fact they do it enthusiastically and even bring it to police

They definitely need warrants, but 99% of the time, people/businesses voluntarily hand it over. In fact they do it enthusiastically and even bring it to police without them even asking. "We believe your camera captured the guy who robbed your neighbor, can we see the footage". Virtually everyone says yes to this.