A dirt path, fine and great. Sounds nice for summertime.
Lot of schools aren’t in a warm climate.
Those paths become unusable in winter, a muddy (unusable) slop when it rains or when the snow melts.
Muddy paths lead to wet socks and dirty shoes at best, and at worst, you slip and get covered.
Either it’s bad enough to ban and should be immediately banned, or it isn’t really that bad and shouldn’t be banned.