IMO, the most important point is to use the camera and not worry about chimeras and internet here-be-dragons stories. Sover Wong knows far more about F2's than I do, but I also imagine he gets in cameras in all conditions, anywhere from heavily used but maintained, to those have sat cocked and forgotten in a bag in a closet for twenty years.
Spring steel has a high yield strength so that it has a large elastic region - when you stretch it within the elastic deformation regime, it returns to shape. That's why it is a spring. It only takes a set if you stretch or bend it into the regime of plastic deformation. Materials aren't perfect, so it is possible that there are springs in cameras that will take a set if you leave them for a really long time. But fundamentally you are more likely to miss a shot by missing focus or getting your finger in front of the lens or any number of other things, than by taking a picture with a camera that was left wound for a week or even a month.