No you are not breaking the law by not sewing with a scant 1/4" seam. The scant is usually one click to the left or right of the center point of the needle. It is used to accommodate the amount of fabric a fold would take up which then makes the finished two pieces more accurate. It really doesn't matter is you are sewing squares or rectangles but might make a differance in fitting if you are piecing other shapes. It is always good to test your seam allowances before piecing to make sure the seam allowances taken make the pieces fit. If you are using one of the quarter inch feet for your machine then it is good to actually measure to make sure it is giving you an accurate seam allowance. All fee are not manufactured the same.