Yeah that "foolproof" idea is rough. My buddy had a sewer line scoped, camera said it was clear. Two months later his basement flooded with backup. Turns out the camera just slid right past a partial collapse because the angle was wrong. He was so mad because he paid extra for the "high tech" check. Sometimes the old school guys poking around actually catch more. Tech is just a tool, it can mess up too.
Ugh, that's so frustrating... @phoenixscott, I feel for your buddy. Had a tenant once where the sewer scope came back clear, then a month later we had a huge backup from roots the camera totally missed. Paid for that 'peace of mind' and got none. Sometimes the guys with years of experience just know where to look better than any gadget. Tech isn't always the answer.
Exactly what @jenkins.viola said about experience... a camera just shows what it's pointed at, but a person knows the weird spots to check. It's like trusting GPS over your own eyes in a place you know. That false sense of security ends up costing more.