For me, it has to do with feeling judged, and trying to decide who I want to share it with. We're still in the closet with everyone except my parents. We visited them recently and took the BBLP and my Dad commented that he had never seen a potty trained 7 month old before. I tried to explain that she wasn't actually potty trained, but he thought the idea was cool and said he had no doubt that she was learning. My mom is getting her own BBLP so we don't have to bring ours.
But I think if I brought the BBLP to my inlaws it would be a whole different story. I figure if I'm not comfortable telling them, then for sure we're going to have more misses.
I wish I had the confidence to say whatever, it's my kid, and parent around others the same way I do at home.