I agree. Liability can be a big problem. I've yet to see a machine shop with a set of bleachers. Engine building is not a spectator event. Now, does that mean you can't call for an update. Nope. If you're worried about something coming up missing, you're at the wrong shop anyways.

Having had two race cars, I think your machinist/engine builder is very much like your doctor. You have to have absolute faith and trust of what's being done to your internals. The engines I had built on the first car were fine. Never had any problems. The second car's engines I build myself for no other reason than I wanted to take ownership of the process.