There are just way too many variables with shots that are lost or out of bounds for WGT to program in which can be retrieved and which can not. As TBE has said the 'creek' that runs through St Andrews is generally only 6 inches deep, although I have seen a couple of feet of water in it before, at places it is only 6 feet wide and the sides are not very deep, however some places, like in front of #1 are probably 4 foot deep, at my advanced age I would never venture into it to retrieve a new Callaway.
Other places are the same. At Kiawah, the hazard on the 2nd hole is not deep and often dry, you can easily pick up a ball but on the back side the hazards to the right of the first few holes are deep lagoons or marshes that you would never venture into.
Out of bounds is similar. I have played many courses where you ball might go out of bounds but be in plain sight and easily picked up. Others there is deep grass, fences, etc. that make it not worth your time. In Florida on a course near Destin, there was a sign saying not to attempt to retrieve your ball, this area is inhabited by rattlesnakes so every area is different. In Hilton Head at a course I was a member at there was a sign on a couple of holes of a wetlands area, you were not allowed to go in to retrieve balls.
It's just too complex. At the higher levels, we don't lose many balls unless we are trying a stupid shot or just miss badly and the penalty then is you lose a ball. Like in real golf the ball you lose is always a new one that you just took out of the sleeve, don't think I"ve every lost one that I was about to take out of play.