I used to do communications consulting for a hospital that received a lot of celebrities, and there are several very good reasons to cut off ongoing updates in a situation like this:
Basic privacy. News that a public figure has been in an accident is generally considered "public" (although not always). But, details about their ongoing medical condition and treatment are a more private matter.
No news. There aren't really any changes and you want to discourage the media from obsessing over every little thing or jumping to incorrect conclusions
Second-guessing. You want to avoid having the media second-guess every decision the medical team or family makes, particular in life-or-death situations.
Dignity. If the patient makes a recovery, they may be very distressed to find out that every detail of their condition has been made public.
"What ifs." If the patient has a life-changing procedure or doesn't make a recovery, it can lead to accusations and speculation about "what could have been done." (Think about the endless discussion about whether they should have transported Diana to the hospital or treated her at the scene.)
Changes in guardianship. Sometimes the initial family members that appear at a person's side are not the ones that call the shots in the long run. Spouses' wishes trump the wishes of parents and siblings in most cases, for example.
Hospitals sometimes request it. Having media around is as much of a headache and pressure for most hospitals as it is for families. They disrupt other patients, staff, and visitors. They require the hospital to bring in additional security, which costs a lot. They create additional concerns about privacy and liability. And, they require a lot of staff time that can be better spent on treating patients and taking care of business.
Peace and quiet. If the media smells a big story somewhere, they probably won't go away regardless of the family's (or hospital's) wishes, but reinforcing the idea that the story "has died down" can help get them on to other things. (But it WILL calm down things on the Internet, since we don't have any medical details to hash over!)
So, I wouldn't draw any conclusions from the "no new reports" announcement. I don't have much medical knowledge, but I do know that it's a good sign whenever someone with a head trauma makes it few the first few days -- that's probably the best news to focus on.
kal