T
The Ghost
I hope the light are IPX7 as it looks like water is going to collect in the gullies. I think I would have used conduit possibly Steel terminate them in with a stuffing gland. They could have used post lights or put the lighting on the walls around it all. But you would still need to mark buried cable with warning tape underground. And at the prescribed depth it may be subject to vandals and people who have had one too many. It is a high risk as is. I can see why someone would have said it wont do. Sorry if that sounds hard I am not knocking you but instinct alone would say this is not right.