I agree, I almost always make a simple phone call beforehand, with one or two recent exceptions, due to an airborne change of plan. Even then we made a radio call on a previous leg to check we could land and refuel on our way back. I've been phoning airfields in advance, PPR or not, for well over 30 years now and have never been made to feel that the call was unwelcome. In some cases, a phone call has prevented severe inconvenience (such as no fuel available for the next two days due to a u/s fuel installation).