The easiest way for ED to get to the PortdelaG from the PicdeS was to go back down to the Cabane de Besurtas. She'd already done that trail 3 times. She'd be able to zoom back down it, and she did have a basic headlamp if she got caught in darkness towards the bottom. No problem for her to get to the Cabane. The next day, she'd ascend to the PortdelaG, perhaps arriving in late afternoon. Evidently, the pathway up the PicdelaG is evident at the PortdelaG.
Upthread, I posted a blog entry detailing exactly that ascent from the Cabane, with photos. It's in Spanish.
This would explain why there are no phone pings. The phone pings still happen in airplane mode, but she was evidently in an area where she wasn't even ping-able evidently, or trackable by the geolocator on her phone (otherwise, they could have tracked her down). This was not true of the Hospice valley. We know there was no cell service at the Cabane, and there may not have been good satellite fixing in the heights of that valley, either.
My two cents:
-I don't understand why anything is being made of the tarptent and its presence or absence. It was with ED or not with ED. Why is it important which? She could've ditched it in town for all we know.
-There would be no reason at all to chase after a tarptent that would have provided very little weather protection anyway. This seems a very unlikely scenario. Note, it was not actually a tent, but more like summer "keep a light rain off" kind of thing; there was no fly; it's just a thin layer of fabric and a bunch of net. You'd let the thing blow away, for gosh sake, if it took off.
-The curiosity for me is why ED ventured up the PicdelaG. I seriously doubt she was peak-bagging. <modsnip - no link>
-IMO deliberate climb to say goodbye at sunset.....
-desperation could easily put you into an otherwise inaccessible place; if you've stopped caring about the world, why would you care if you fell catastrophically trying to get to a catastrophically-located ledge?
I have been in favor of accident this whole time since ED went missing. Up to now, my picture had it the accident occurred while descending, on the French side, from the PortdelaG. But I see no compunction to climb PicdelaG except to say goodbye to the world. And, as I look at the preceding days, the events that unfolded secure my opinion that this is what happened.