The first machines I used were zigzaggers, a Bernina, a Husqvarna, along with a 99K. At the time they weren't vintage as much as just not the latest. Now 30 years later they are. The stitch selection and zigzag settings isn't a problem, just tell them they are set for straight stitch and that's what you are going to use. Playing around with settings shouldn't be much of a problem if they want too? I consider all of these nice machines to be handled with care, but some place has to be for new commers too.