I beg to differ. Farms are not legally required to have PL insurance. Employers liability yes but not Public Liability.A farm business does have to have public liability insurance. It covers all sorts of eventualities, such as injury to people using public footpaths that run through the land, people using the land with permission, people using the land without permission (trespassers), delivery drivers entering the property, etc etc.
Maybe this is what was being referred to?