Well, John as a long time, presumably Colorado skier - you are wrong.
Open ski runs often have unmarked obstacles / hazards. Man-made items - lift towers, snow-guns, trail signs, and the like, which may be marked, fenced, and/or padded - as required by CRS. But, if man-made obstacles are visible from ~100 feet the requirements change.
Me? I have ~110 days between the ropes this year and ~20 or so in the backcountry.
Want to join me for a day on the slopes - probably not - but if you did, I will show you numberous unmarked obstacles on open runs. I've got 'core shots' on numerous pairs of skis as a testament to these obstacles.
I bet you would assume that a Colorado ski area would be liable for an in-bounds avalanche resulting in injury? Maybe not. Read the Winter Park and Taft cases for details.
You may wish familarize yourself with
2016 Colorado Revised Statutes, Title 33 - Parks and Wildlife Recreational Areas and Ski SafetyArticle 44 - Ski Safety and Liability § 33-44-107. Duties of ski area operators - signs and notices required for skiers' information33-44-107. Duties of ski area operators - signs and notices required for skiers' information
(7) The ski area operator shall mark hydrants, water pipes, and all other man-made structures on slopes and trails which are not readily visible to skiers under conditions of ordinary visibility from a distance of at least one hundred feet and shall adequately and appropriately cover such obstructions with a shock-absorbent material that will lessen injuries.
Dive operators should be so lucky as to enjoy the liability protection afforded to Colorado ski operators by state law.
Notwithstanding any judicial decision or any other law or statute to the contrary, including but not limited to sections 13-21-111 and 13-21-111.7, C.R.S., no skier may make any claim against or recover from any ski area operator for injury resulting from any of the inherent dangers and risks of skiing.
"Inherent dangers and risks of skiing"
... means those dangers or conditions that are part of the sport of skiing, including changing weather conditions; snow conditions as they exist or may change, such as ice, hard pack, powder, packed powder, wind pack, corn, crust, slush, cut-up snow, and machine- made snow; surface or subsurface conditions such as bare spots, forest growth, rocks, stumps, streambeds, cliffs, extreme terrain, and trees, or other natural objects, and collisions with such natural objects; impact with lift towers, signs, posts, fences or enclosures, hydrants, water pipes, or other man- made structures and their components; variations in steepness or terrain, whether natural or as a result of slope design, snowmaking or grooming operations, including but not limited to roads, freestyle terrain, jumps, and catwalks or other terrain modifications; collisions with other skiers; and the failure of skiers to ski within their own abilities.