I love it! Generally I create art quilts - mainly because I don't like "rules". If I want to, I paint over anything that needs a different color, if it is sticking up, I glue it down, if a thread shows, I use a marker on it. If you think your sister is making you nuts, just consider the effect I would have on her!!
Every new quilter needs "rules" as a guide to get her started. This too shall pass. Congrats on introducing her to our world, we are happy to have her!!