"The Liturgical Police" above was myself wearing a funny hat. Some friends of mine, years ago, invented the Liturgical Police. It is a joke-concept which, to my observation, serves two functions: (1) A lighthearted way of poking fun, without actually being insulting, at people who are a little too strict about rubrics; and (2) when one does abide by the rubrics (which sometimes actually make sense), feigning a fear of the Liturgical Police provides a way of being serious about correct procedure while retaining a touch of good humor. (Perhaps your musical director accomplishes the same end by being a banjo player? Sorry, I couldn't resist.)

Maybe the lady's disapproval could be assuaged by a scripture citation ? The 150th Psalm (among others) approves of the use of cymbals and tambourines in worship. Your cabasa sounds like it would stretch the meaning of those words a bit, but perhaps it could be considered a sort of combined timbrel-and-cymbal.

T.