Designers - do you take other designers classes?



A friend asked me the question of this post's title privately some time ago.
 
I hadn't intended to write a blog post on this topic until I was asked the same question again later by someone else. That tells me that this is a topic that people just aren't sure what the correct etiquette should be. I've taken many classes from other designers. All were before I decided to take my chances in the professional Knitting world and launch my own patterns and teaching career. I love both taking and teaching classes, it is the ultimate in fun for me. Personally I would feel honoured if another designer wanted to take one of my classes. However, now that we are talking about this I think if I decide to take another teacher's class maybe I had better ask for permission from the instructor first. What do you think? Has anyone got any good advice to share?