Re: Underqualified Sensei
Not all organizations are linked to Honbu and so there are many perfectly valid black belt level instructors out there who do not have an IAF card. Even so, I doubt very much that you could call Honbu up and ask about a particular instructor.
I think the real key, here, in lineage - what is the person's link back to O'Sensei. If an instructor is open about explaining that, then they are probably going represent themselves all right in general. They may or may not be good teachers, nice people, etc., but at least you'll know their background. On the other hand, if they claim an oddly high rank, or to have beaten Chuck Norris in thumb wrestling, etc, then there may be a problem.....
PS For what it's worth, here's how I would answer that question: I'm sandan, I've been training for 20 years, and I started a dojo so I could keep training. My first senior teacher was Akira Tohei Shihan. Now I am a member of the ASU and am a student of Saotome Shihan (through his senior students) and Ikeda Shihan (who promoted me to my current rank). My other teacher, and the central influence on my aikido training today, is Mary Heiny Sensei. Tohei Sensei and Saotome Sensei were direct students of O'Sensei. Ikeda Sensei is Saotome Sensei's senior student. Mary Heiny Sensei is a student of Hikitsuchi Sensei (10th Dan), who was a student of O'Sensei for decades.