The problem is that it can take some time before the Hertz staff start to recognize you by name and your face. One "hello' is unlikely to do it! I would not recommend going to the counter for no reason, that's likely to get you the wrong type of recognition - the type you don't want
If you are willing to buy up a couple of times, then go to the car, get the paperwork and go to the counter and ask for an upgrade. - If you hear high-prices don't take the upgrade! If like me, you find yourself with an occasionally high rate, then always go to the counter and ask for an upgrade! Tell them how much you are paying and you'd like an upgrade because of the high cost. After a few times they should get to know you.
As always, an upgrade is never guaranteed, even for PC. If you have a very cheap rate and long-term rentals, both these factors will reduce your chances of getting any upgrade. Upgrades are more likely, for short-term rentals and high tariffs. It's also luck of the draw.
My last piece of advice is to always be civil with the Hertz staff, even when you don't get what you want - they always remember the nice people.
