You cannot undo anything that's history, including not testing. If you missed a chance to get other tests or treatment early in life, you don't get the chance to fix that later either.
It would be easier to be cautious on penetrance, and reevaluate later, than to never collect the data and hope something changes. The number of these calls to limit our access to data are piling up, and they shouldn't be taken one at a time.