Yes, there has to be a very good reason in order to get a PPR. Dropping in for novelty aspect won't cut it. Would be neat if it could, but the government doesn't want the liability, hassle, etc, etc, when it's not at all needed. Like I said, some bases won't even allow other military aircraft to get a PPR unless there's some specific business they have at that base, besides just a XC or fueling stop.