as a cowboy chord guitarist and veteran of years in 60s pop bands and folk bands i've never ever noticed jazz chords turning up unwanted in BIAB folk and pop styles. maybe its because i've set the preferences the way i like - no embellishments and simple arrangements. this thread started out with a genuine problem in BIAB - a key change where the RealTracks players used 7ths the way live musicians would do seeing a B chord in the key of A. for my three chord songs i use the root, sub dominant and dominant chords - and if i don't like the dominant seventh in some places i don't use it. thread drift seems to suggest that BIAB won't do as it's told completely out of context of the original post.