I'm currently going through the game again and a thought strikes me. Laura goes to a lot of parties and outings without the MC. has anybody ever noticed this? It just feels weirdly disconnected that just about every social gathering she goes too is without him. I could get behind a scene of them both at at bar and the MC is watching and texting her while she flirts with somebody.
The game is based on the events happening on the phone, but in game we see time passing in the form of "X hours passed" to "X days passed".
So to me at least it means outside of the phone they are probably doing things togeather, such as the parties you mentioned and just regular hanging out days with the GF and her friends.
(Which would be why everyone is so close and comfortable togeather.)
Your suggestion though is a good one, would definitly help fill in some of the plot holes, and mix things up a bit.
Maybe if the developer is willing to step away from the phone concept for one of the endings scenes were the MC is in the room, I could see that as being pauseable, unless they're strickly staying with the phone bit for 100% of the game.
If that's the case maybe throw the MC in the closet in one scene, have him able to read what the GF is typing but at the same time realize that she's not telling the whole truth anymore depending on her level of corruption and the route you took.