Yes, I do a lot of single note fills on the middle four strings. I was mentioning that in my comment below, when backing up other song circle participants. If I was uncapoed, and someone was playing something in Bb, or some other non-friendly key, I could find my notes on the neck and work around what they were playing, just like being in standard tuning on the A, D, and G strings. I always made a point of not playing louder than the person who was singing.