lonecoyote
IMHO I think that going to a seminar can be a great way for you to get some added experience from a different instructor or in a different martial art. I have attended many different types of martial art seminars over the years, some in tradtional martial arts, filipino martial arts, JKD, Kobudo, Aikijujitsu, Kenpo, karate, and others. They all are different and you can do different things at each of them (etiquette wise and all). Here are my suggestions.
1) By all means stop by and talk to the instructor and ask him what the proper etiquette will be for the seminar. Should you wear your gi and rank or should you wear a white belt (if it is not your primary system). The hosting instructor can give advice on this and you can ask in such a way as to be respectful to him and not sound like a complete idot or a braggart. In fact talking to the insitrcutor and being pleasent and respectful can generally help you out in other ways as well (who knows he might assign on of his students to work with you, or introduce you to the instructor who is teaching etc. etc.).
2) Should you take notes? This is a hard one to answer. Normally I really advocate taking notes, in fact I taken a bunch (pages upon pages of them). However in the grappling areas I have taken very few. Because grappling is hard to really get a handle on especially if you aren't normally in the grappling art. In that area you might be better off just trying to experience the seminar and try and pick up what few techniques you can. Also with taking notes it helps if you have a short hand system already worked out ahead of time. Also it might be improper (again ask the host instructor).
As a side note I once met a guy who was a sketch artist (he drew for fun) and he drew sketches of grapling techniques as the instructor was teaching. Man I wish I had that talent

. That was the best form of note taking for grappling I have seen. He could have illustrated a book, not super detailed but his style allowed for a very clear picture of what the technique was. And of course he filled it in during breaks and such.
3) How to get the most of the seminar? Arrive on time or early for that matter. Be cool to whomever you work with. Don't try and counter the techniques the instructor is teaching or work on your own system when you should be working on what the instructor is teaching.
On a side note I've run into this several times, instead of working on what the instructor is showing, seminar participants are doing thier own thing. I've seen completely different drills / techniques being done by other BB instructors instead of what the teacher is showing. Sorry I'll get off of my soap box. :soapbox:
Instead "empty your cup" and try and enjoy your self. Be nice and respectful, pleasent, non confrontational (about whose system is better etc. etc.), don't be a know it all.
Bring some extra money in case they have videos, shirts or something like that to buy (if you are interested, this is another way for the host or the visiting instructor to meet their expenses). Also maybe bring something for a snack to eat / drink (if it will be a long one). Maybe a camera (if it's allowed). And if you could bring a training buddy so you can work on the material after the seminar.
Or you might want to set up one (training buddy) to work with immediatly after the seminar and better yet video tape what you remember of the material you covered. The sooner the better.
Oh well I hope I have given you some decent advice on how to have a good time at the seminar. Please post a review of it when it's over.
With respect
Mark