Doesn't this depend on flight attendants and whether they follow the service standards or not? I've had a purser follow the even/odd rule. I've had others that seemed to go off the manifest, starting with diamonds. Other times they have went to random seats with no discernible pattern or method, so much so that as a paid business-class passenger with diamond status sitting halfway in the cabin on the A side I was the last asked. Other pursuers have deliberately went to non-revenue passengers last.