First I want to say that I in no way am defending what these soldiers did but just wanted to ad some perspective to this.
Now this was a while ago and regulations may have changed but from what I've heard they handle things close to the same now.
When we would travel with the President, once with the VP, they would have at least one floor of the hotel secured for POTUS and some of his senior staff. This floor was secured tight, you only entered that floor if they requested you be there. The rest of us would stay on different floors. The floor for POTUS was secure, but the rest of the hotel was considered technically secure, meaning they had swept the place and had personnel stationed about the building.
While the entire hotel was considered secure it was still filled with regular guests, I remember once that we had the Boston College Cheerleaders staying in the rooms next to us. I only mention this because when the press wrote that they brought these women into a secure area, it was probably not the type of secure area you would first think of. We would sometimes walk out our room to see Mom and Dad with 3 kids in bathing suits heading for the pool.
So while these soldiers probably broke the rules the level of security may not be as large an issue as the press reported. Should they have been reassigned, yes, and I'm sure they will no longer hold those positions and they could take a hit with their security clearance, and their service record will take a hit.....And if any were married, well, that's a whole different issue.
The issue with the AF cadet was different, he actually brought an unauthorized person on to a Military facility without permission and broke clearly spelled out rules and regulations for cadets. While it seems the same there is a difference when it comes to the military. The other point is that the hotel the soldiers were staying fell under the security of the Secret Service and was not a Military property, the rules are different.
I have no doubt these soldiers will be punished and their careers will take a hit but I doubt they will be removed from service, of course they will need to be promoted some day and that's another issue.