I agree totally...
Seminars are a great thing, both for improving the style you usually practice in, and for learning new ways of seeing/doing things..
As for students not attending seminars at their own dojo, Mr Ledyard, I just can't credit it!
We get very few seminars here in the UK, seldom easy to reach without a car, but I'm hoping to attend as many as I can - style is unimportant
Cost can be a factor, obviously, and I have seen some very pricey seminars advertised on the web (primarily for US dojo - not Ledyard Sensei's though