This is a very good example of why the guidelines are important! Saying that its a landing zone and expecting someone coming in from a different line to be aware of that is unreasonable. This is not where there is a marked trail that you are skiing into, but an entire hill that is whatever trail that you can ski.
While the uphill skier carries to greatest responsibility, it is still important to sitiuasionaly aware so that don't ski into a bad situation. Looking at the second video is a good example as you clearly see multiple lines and runs made by numerous skiers. That alone should be a warning that there is risk of collision as it has become a popular and crowded spot. The lucky thing is that no one was hurt and over all both were civil with one another, but it could have been a lot worse.
Years ago when I was young and stupid, we used to jump into blind spots at full tilt, in those cases we always posted a spotter at the take off point (or there about) that could see the landing zone and surrounding area, along with the start zone and signal the all clear. Even then it was risky, but for the most part avoided any collisions or near collisions. Back then ski patrol gave us more freedom as we policed ourselves to prevent injury to others (self inflicted was another matter), it appears that ski patrol now has less tolerance, however I see less caring about others now by certain individuals, so I understand this lower tolerance level.