Ranks aquired at other places
My issue with this is not the ranks themselves, rather the person who shows up at the dojo, makes it perfectly clear they want to attain shodan with no thought about etiquette, tradition, principles, etc, and insists on shoving their certificates in my face to prove they were worthy.
I had this happen twice within 3 months. Two students, seeking shodan. Neither belong to an organization that could be traced back to any major group or instructor. Watching them take ukemi was painful and one could not even make nikajo work on 14 year old. But yet they both wanted me to grade them to shodan. Neither would take advise or instruction and refused to do things in our manner, thus putting our students in a dangerous situation.
One boasted about how great his ukemi was. Not a good thing as I but that to the test. Needless to say, he crashed and burned then complained about how hard I through him and barked even louder for making him tap out of my osae waza. Too funny!
On the other side of this of this, I had a nidan from the Aikikai train with me for a while and his only desire was to learn. To me it doesn't matter as long as the person respects our customs and makes an effort to learn our ways.
That's my nickles worth anyway ...