Paul Kozlovskis wrote:
As a personal feeling, I believe mudansha (if training elsewhere) should follow the general guidelines of the dojo they visit. If only their yudansha wear hakama, it's probably best that you don't etc.
I think the best policy is always to ask what is permissible or expected. I've found that for short visits, people don't usually care what you wear, but it's always best to ask first.