For my 2 flights this week, an offer of water.
I did hear a passenger in First gripe about not getting "champagne". Although nothing besides water was served before take off, I liked how the flight attendant did ask for beverage orders before takeoff.
The pre departure beverage service is regularly absent. It is so regular that I now never expect a pre departure beverage other than water. So, I need to bring my own coffee on board. The absence of a pre departure beverage is so regular, that I conclude it is not part of the policy or management does not really intend to make that policy happen.
As far as reporting pre-departure beverages, wouldn't it be easier to just report the exceptions: if more than water is offered before departure?