You say "I've hit ummarked private electric lines to shed and outhouses!"
You don't carry a locator with you to locate that stuff? Dog fences, lamp posts, pool power, well head power, shed power.......I locate all of that myself.
As far as irrigation, I will turn the system on and mark the heads. Then plow in the conduit, then turn the irrigation system on again, watch for all of the heads to pop up, if they don't, simply walk the trench and you'll see a pool of water bubbling up, open that up and fix it on the spot with $1 worth of materials. Or I tell the homeowner if they find that I did cut it to call me and I'll be out to repair for a few bucks instead of getting the $100-$200 repair bill.
