A lot depends upon the individual P/FJ location. Some appear to be 'franchisee' locations that don't honor some parts of the P/FJ programs.
For Example this one in Montana has RV lanes, but only gives RV rewards in the truck lanes. - http://www.pilotflyingj.com/view-location?id=0968
There is a 'franchisee' called Town Pump that apparently doesn't honor discounts at all.
Some in Ohio appear to not honor anything related to discounts or rewards.
The Bosselman group in Missouri and Nebraska appears to have their own rewards card system separate from P/FJ.
The printed P/FJ directory makes it easier to see locations that don't honor the programs than the on-line search.