Hell I wouldn't be surprised if Allisons phone was in Gerard pocket the whole morning of the reported disappearance. It was safe and sound. Gerard could check that Allison's phone had received his texts that would be really positive for him. I can just see him saying 'great that text has come through' what should I say next.....
Then after GBC had called his Dad over he would have given it to NBC. Much later it was disposed somewhere far away probably by NBC.
The thing that gets me is that there is no hint of a use of prepaids. This is common element between people who want to hide things particularly affiars. I can't believe GBC was so brazenly cunning that he wrote all his messages on his iPhone. One slip up to Toni or Allison or the many women and he is revealed.
I once wrote a message to my husband and sent it by accident to my youngest son. I was telling hubby how badly behaved my youngest son was at sport. It was an inane message just relating that I was so angry I could have swung him around by his hair. I ended up getting my older son to delete the conversation on the younger ones phone, cos it was simply me expressing my anger but I didn't want the youngest to read it even tho it was funny and moderately innane. This was harmless in the context of a mistake. The stakes were MUCH higher with GBC and his sexual encounters and dalliances!