Easy solution for a pro-PPR airport :
Add 10% to all landing fees, with the proviso that by getting the PPR, a 10% discount on the landing will be given.
If you don't like it, don't go there......
Well, sure, I could do that in my business, too. All prices go up by 10% unless the customer phones up first to ask if we will sell to him. Jesus.
If you want to keep your private strip exclusive (and you well might) then keep it that way. And keep it out of all the farm strip directories so that, god forbid, nobody gets the idea to fly there. But if you have an established airfield, don't go round pretending it is open to inbound aircraft and needs a PPR.