To sort of get this back on topic, I suspect one of the reasons none of have written much more is because L7 did a great job explaining some specifics.
I don't know of any set procedures about grooming at any resort and certainly not industry wide. (Someone want to enlighten us otherwise?)
People who operate cats tend to be some of the most experienced people on the staff of a ski resort. Whereas your marketing and accounting staff might only work at a resort for 5 or 6 years, it's not uncommon to find slope maintenance staff who've been around 20 or 30 years. These guys have spent A LOT of time on the mountain. A little common sense in this area goes a long way. A lot of times they make the decision at the beginning of the shift on what's going to get groomed. Intermediate runs are especially odd. Whereas most green circles get groomed every night and there's usually a few black diamonds that always get groomed, there's not necessarily any rhyme or reason when to groom an intermediate run. They can be some of the variable slopes on the mountain. Grooming an entire (western) resort every night isn't very practical. It's better to groom, say, a third of the intermediate runs each night during the week and then Saturday and Sunday.
That's why Breck likes to advertise their "every blue and green every night" approach to grooming. That's A LOT of grooming. Similarly, Beaver Creek maintains a high state of grooming. (Mostly because the rich pansies suck at skiing and tend to whine if they can't ski on corduroy.) If you're looking for places to contact about grooming methodology, I'd start there.
How grooming is done differs everywhere. Breck likes to go gang-grooming (my friend who runs a cat at Keystone calls it something else, I forget what.) Basically 4 cats line up side by side and drive up and down the hill together. I'm guessing that's a good way to get the new groomers up to speed with the experienced guys. Other places (Snowmass comes to mind) I've seen cats operating in teams of two. I think a lot of places send cats solo to specific areas. These days, terrain parks have dedicated crews and equipment. The park is generally off limits to everyone else.
With regard to marking hazards, it's done differently at every resort. I don't think there's any specific rule as to who must mark things. Sure, ski patrol marks stuff, so does slope maintenance. Other groups may mark things at their whim. For example, I've seen the snowmaking crews at Loveland marking their stuff on their own.
Personally, I got burned a few years ago by grooming. We have a run I like to ski that's sometimes groomed. There's a fast intermediate trail that leads to this black diamond. The previous day I'd skied the run and it was well-groomed. The next day (just a few ski hours later) I came screaming down the intermediate trail going REALLY fast. I approached the black diamond and immediately saw the bump field in front of me. Now, no one was skiing there so I decided to see if I could bleed some speed.. but it didn't work.. I made it through about 3 bumps going way too fast before slowly breaking apart. I definitely made a mistake expecting it to still be groomed, but at least I walked away from it.
I just thought of something.. if I sued a ski area for negligence and I lose, do I have to pay their court costs? It makes sense people should, but I suspect since that would decrease litigation the lawyers who make the laws wouldn't be for it.