I don't think that's a good sign she wants to hide who's calling...I also don't think you should have to snoop...but I totally understand and have seen both sides of people hiding things or being open. I once had a bf that his phone would be going off at all hrs and if I asked who he was txt or why the msg at weird hrs he shut me down and said it wasn't any of my business...by his actions it was 'then' that I got suspicious...one evening he'd fallen asleep and his phone ws literally in front of my face so I saw the txt that came in..it was from a former gf(who I found out he was still seeing)..when I confronted him he went bizerk...basically bc he got caught....My current bf said upfront that any time I wanted to look at his phone to go ahead...I haven't really felt like I need to..but once we went through our msg together..so..we are both confident w/ea other...I believe in privacy but when someone gets defensive and weird when you ask...just from my own experience..they don't want you seeing something..and hiding/secrecy often leads to mistrust and further problems...Ask her if just one time you can put your mind at ease and you won't ask to see the phone again..if she says no then I would bbe concerned she's hiding something..pretty sure she wouldn't like you hiding things right? Good luck