If I'm going to someone else's class (in Japan for instance), or attending some other instructor's seminar, I always bring the full uwagi and adjust to what that instructor and his own students are wearing. Likewise, if we bring in an instructor from elsewhere for a seminar, I expect my own students who may attend to bring the whole kit & caboodle and similarly adjust to that instructor's comfort level.
A core concept of ninjutsu is being able to "fit in", after all. . .
Absolutely Dale,
Fitting in and being respectful based on what another teacher expects is an excellent approach.