Almost buried a sprinkler line because my own locator ticket was wrong

I was running a small trench job at a strip mall out in Mesa last Tuesday and the 811 locate marks for the irrigation came back clean, so my operator started cutting at 7am. About 40 feet in, the bucket popped a 2 inch PVC line and water started shooting maybe 15 feet in the air while the tenant's staff stood in the parking lot watching us. I killed the job right there, called the water district, and found out the locator had marked an old abandoned line and never flagged the live one. I ate about $900 in repair and emergency shutoff, then started making my operators hand-dig test holes every 25 feet on anything near a marked line, no exceptions. How do you all handle it when the ticket itself is the thing that's wrong?