I don't think it's a problem as long as you aren't selling them. You're not making templates with a hole in them, which might put you on shakier ground. Your're making 2 square templates - and for Fun N Done you'll use one 2" smaller than the other. And you can use the rest of the plexiglass to make all different size squares and rectangles - and triangles, for that matter. Mark the sizes with Sharpies on masking tape.