I can't really speak to how it is with Aikido in particular, but I've found that in the art I practice as a kyu rank when I approach yudansha at seminars and ask if I can work in with them they're generally pretty happy to oblige, and often flattered.
They do not, however, tend to actively seek out kyu ranks, and left to themselves tend to mingle with others of similar rank.
Carl Hamlin
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'The etiquette that underlies all martial arts is based on the assumption that the person with whom you are dealing is standing before you wearing three feet of razor sharp steel.' - George Ledyard