[liber8]

I don't envision this being a problem at all. First, its easy enough to have a checkbox that says "I saw it, here's the feed you want." (In all likelihood, if anybody committed a crime in downtown Manhattan where hundreds of people were around, the cops wouldn't have any need to ask the public for data anyway.)

If nobody saw it (or doesn't know what they were looking at, as would usually be the case if they saw a getaway car), I still don't think there will be a firehose of data. The feed will already be geotagged and time stamped, making it easy to sift through by hand. Plus, much of this can be automated, even with the relatively rudimentary recognition software we have now.