Nice post, I agree.
If he were to bury something, wouldn't he have had to have done it several days prior to the pour? Not sure he would have been able to get his compaction passed if he spent 30 minutes during the night burying something? If it was buried deep then in my eyes that would be much more difficult (& noticeable) with a pour a day or two later, possibly if back filled with aggregate.
In my opinion; I have this thought the dig was a witch hunt. There are a lot of things that could have had last minute excavation on. The late night equipment use could have been something as simple as he needed that equipment in Denver and knew he had to use it quickly at that job. Being a small time operator he could have just needed to wrap up something and get the equipment loaded for the next job, because that was the only piece of equipment he had.
In my day, I would make sure family time was had then I had a few late night job site checks, but mostly after everyone was snoring, I was in the office catching up.
This was a slab pour, as you know there is a lot of activity on that grade right before pouring, IMO it would have been pretty tough to bury something a couple of days prior and not have it noticed, fresh gravel would red flag an inspector, or at least have him inspect/ask. There are guys double checking everything(plumbing/electrical/drainage/forms/etc.) and walking all around up until the pour. Especially if its a Monday or Tuesday pour with signs of a fresh gravel area /compaction(excavation) that appeared over the weekend without any prior notice.
