In some police departments, there is a requirement that body camera (OBRD, BWC, different departments like to use different terms) footage be uploaded after every call for service or reported incident, officers are audited against this requirement, and missing footage is an infraction subject to suspension without pay. In some departments, there is no policy at all, and no interest in creating one.

The biggest vendor, Axon, has a fairly well-designed system for video management where the auditing system makes it fairly easy to determine whether or not footage exists and why (e.g. cameras log all deletion of footage e.g. due to full storage and report it at the next upload, the management system reports on cameras that have not uploaded for more than two shifts, video once uploaded cannot be deleted until the end of routine retention even if not associated with any incident). This is not to portray Axon as a saint, because there are questions about the auditability of their evidence.com product specifically when it comes to preparation of video footage for court or public release, and this can be a material problem. But it also makes it even more troubling that some departments, district attorneys, etc. make no effort to use the auditability features that exist, or routinely accept sketchy excuses that are not consistent with the audit record.

These aren’t technical limitations, and there are a lot of police agencies - a few who are on top of things and see it as a way of keeping their officers honest and getting to the truth, and a lot of them looking to CYA.