I'm going to have to agree with S97, the landowner should have informed him that he took steps to eradicate the rats if they had something previously planned out. In all fairness, it was most likely a simple oversight. That being said, courtesy goes both ways.
I guess it depends on the type of permission agreement. Obviously, the owner has a pest problem. However, because the pester (S97) is not being paid to eradicate the pest, the *permission* is a courtesy of and by the owner. Yes, the pester is doing a service, but I doubt any airgun pester ever eradicates the pests.
So, I have to disagree here. Pesters (myself included although I only pest in my own backyard) like killing pests and without pest targets, at least for me since I don't plink or shoot targets for fun, we pesters have a dilemma. Some people seek out *permissions* so as to have pests to shoot. Given that the airgunner is MUCH less than likely to eradicate the pest problem, the owner of the permission is really doing the pester (airgunner) a favor by providing the "targets" and range for free.
Anyway, yes, courtesy works both ways, but IMHO, the owner deserves the MOST courtesy because without them you would have nothing and nowhere to shoot.
JMHO and no, I have never shot pests on a *permission* unless you want to count my former neighbor who allowed me to shoot over his (he rented actually) property.
So, IMHO, the owner owes the pester nothing. The pester owes the owner everything.