This thread brings up some interesting issues.
1. When I travel, I usually try to make contact ahead of time if I would like to visit an out-of-town dojo. Sometimes, however, I'm not able to speak to someone at the dojo because of limited class times, and I feel bad about leaving a message and placing an obligation on the dojo to return a long distance call to give me the OK to visit. E-mail is a great solution to this, but not every dojo has it. On the other hand, I have always been made to feel extremely welcome at every dojo that I have ever visited, whether or not I have been able to make contact beforehand.
2. I my home dojo, it is our custom that only yudansha wear hakama. However, I know that in many dojos, hakamas are worn by all ranks. What is the correct protocol when I am visiting these dojos? Do I need to purchase a hakama for these occasions, or is it usually OK for me to go in my "underwear?" On the one occasion that I did visit such a dojo, I was still unranked and the Sensei had formally been affiliated with our organization, so he understood and let it go.
3. In one dojo I visited, I was asked to line up ahead of the sempai (mostly yudansha), even though I was a lower ranked kohai (mudansha). What are other people's experiences in this area?