I'm amazed this myth is still in circulation. If you have no signal from your operator but have some signal from another operator, you can still call emergency services. If you have no signal at all, you cannot call anyone. Period. And even if you do have a signal to call emergency services, it can still make sense to leave your climbing partner on the mountain while you go to get help. You know exactly where your partner is, so can help the emergency services find them. Indeed, according to the defence, Kerstin told Thomas to go and get help and, when he had second thoughts and returned, told him to go on his own and save his own life. Of course, we have no way of knowing whether this is true.
It is concerning that there does not appear to be any recording of the call Thomas P made at 00:35. The police say he told them everything was fine. He says he called for help. If the rescue attempts had started then, she may have survived. Why would anyone call the police to tell them everything was fine? If he did, that seems very odd behaviour. If he is correct that he called for help, her death may be down to the police's failure to act on that call. By the way, it is the prosecution's case that he put his phone on silent but here is no evidence that he actually did so. He says he did not, but that he simply didn't hear the calls and that he didn't feel his phone vibrating.
I wouldn't read anything into the state she was in when she was found. As others have said, people suffering from hypothermia often behave in bizarre ways.
I do wonder if they had summit fever - something that can affect mountaineers when they get close to a summit, leading to them pushing on to reach the summit ignoring risks. This often leads to fatal decision making near the summit. They were only about 50m from the summit.
It seems there is at least some evidence that she was nowhere near as inexperienced as the prosecution claimed, with her social media feed suggesting she was a keen mountaineer. Indeed, her parents wrote a letter saying that they don't blame him for what happened and that she had summited mountains far more difficult than this one. But one of the risks with romantic partners climbing with each other is that they may push too hard, trying to impress each other.
Nearly 300 people a year die on Austria's mountains. Criminal proceedings are almost non-existent. The question is whether this was a tragic accident or did his actions constitute gross negligence.