I think that makes his lineage fail the test of solidity.
The first seminar I attended with Dan I found very informative and good. I wanted to know his lineage, who he learned from, who did they learn from etc. I could have just blurted the question on the floor, but i believe in martial etiquette.
So after the class I waited because as I've come to learn he gets surrounded by people still practicing and wanting more and Dan just keeps talking and talking...
Finally I got him aside and I asked him.... and... he told me. No big deal. Meet him and ask him. I don't want to put words in Dan's mouth, but listening to him at his seminars it comes across to me that the lineage thing to Dan is about Ueshiba and the other giants and not about Dan.
If I'm not mistaken in Koryu there is a culture where you never show someone else your Menkyo scrolls, its personal and private - Not saying Dan is a Menkyo holder or anything, I'm just talking to the etiquette that still exists in some forms of Budo and isn't meant for forum discussion. IMO