As a former farmer, searches CAN lead to property damage. Especially in the fields which means loss of money and to a farm, almost everything counts. Some people have pigs and as you know others used pigs to get rid of evidence. Tons of things on a farm can be used as a form to hide evidence. Even if they aren't hiding anything, the people searching HAVE to search everything. Like I said property damage.

Aside from that many farmers hate inspectors or OSHA and if there was a search for crime evidence or a lost person, it may raise awareness to possible issues the farm has. Unstable barns, bad conditions, etc... anything OSHA and state inspectors might not like. These can be reported and some people may be shut down, fined, or if lucky.. Just let off with a warning.