Laurie wasn't spotted for a good chunk of the second half at casey, not sure if it was injury or perhaps pulled out for cover in case of a late withdrawal for the seniors.
100mfc games gets his name on the #18 locker and father/son eligibility.
Not saying it's the best reason, and may not be accurate, but with due respect to Melksham I can't think of many other reasons for him to be selected, even as sub.