I think that this is the way to go because it's really hard to catch all of the things that can go on on site if you're not a professional. I built (ok got fellas in to build) an extension many years ago and I didn't catch that the drainage was inadequate until after they had completed and left - so I had to get that done separately and it wasn't cheap. Every builder I've talked to since has given me the impression that they would have spotted this upfront, and I think I believe them.

> I imagine the better way is to hire an experienced GC to go and check on it every day for you.

Going every day is how you check the GCs work. A good GC should probably tell you the days where it's more important for you to come and check and what you should be looking for, but being there to notice things and ask questions helps keep things on track.