I think a small fee was proposed - never heard the final word from the Class. I don't have a problem with other boats getting weighed on the Class scales, especially if there's a small revenue stream to help offset the cost of the scales/maint/transport.
...Not to mention the time of the F18 class people to do the weighing. When we were at Spring Fever, Tracie and others were on the job all day, just weighing the F18's. These are not bathroom scales -- they are pretty high-tech.