Ah, yeah, there's that.
I'm inclined to test this theory on the next few flights. I'll report back...

Yep I haven't asked for anything else for ages. On a morning flight with SO, we'll ask for mimosa if not offered, but that's been many moons ago.

IME on many dozens of flights over the last couple years (since PDB return in 2021), I have almost always received my request for a PDB bloody mary. On those few occasions when I have not been accommodated, it has always been politely declined and explained that it will have to wait until we are in flight. When declined, I always say, "I totally understand, but if you there is time before we depart, I would definitely appreciate it". And probably half the time, even though explicitly declined at first, I am eventually accommodated before departure. I have never even once received a rude or exasperated response to any of my requests.

Mostly for my curiosity, but what do you do if the FA just sits/stands there gabbing with the other FA's after boarding is completed and you've still got 10-15 minutes left before they close the door?
Do you ring the call button or approach them to ask about a PDB?

(Only had this happen once on UA, once on DL, and multiple times on AA). I never got the courage to ask.

proceed with caution!!!!!

Approach them abruptly, and say in a loud voice: "Hey, YOU!"
/s

You sneak behind them why they are distracted and help yourself to whatever takes your fancy :-)

Why?????

Backlash? (See post #255)

Nonesense!

not in my opinion. FAs now all have an attitude given very poor management and inconsistency. If you ask for something simple as an alternative PDB than get ready for an argument.

Come on. I can barely get them to take my jacket before departure and to even get it back before landing. And your response is “nonsense”?

As I pointed out above, this is not at all my recent experience on many dozens of flights on United Airlines over the last couple years (and many hundreds of flights over decades). As is abundantly clear reading this forum, based on the reports (undoubtedly all sincere) of UA experiences of FlyerTalk flyers, one would conclude that there are two completely different airlines doing business as "United Airlines". My theory is that FAs, TAs, GAs, etc (like all customer service workers across the retail economy) are extremely attuned to and perceptive of the "vibe" & attitude of each customer, and respond accordingly. Of course, it is certainly arguable that true professionalism would preclude responding differently to each customer on this basis, absent flagrant customer discourtesy.

In over forty years of flying, I have only ever rang the call button once, and it was because I mistook it for the light switch.

All I can relate is my experiences, as the other poster did. In my flying I have never been afraid of retribution by a FA (nor have I seen such an experience). Yes, very occasionally, a FAs may be inattentive / abrupt / snarly / .... And yes some customers, typically very inebriated, have been taken off a flight (and the infamous Dao incident which was a complex situation handled badly and not by FAs). But asking for PDB, that's nonesense IME.

so what you’ve saying is that customers have the right to politely push back if their choice of PDB is rejected? Maybe that would have worked in the past. It doesn’t fly these days. Yes I agree some FAs would be glad to get ur choice of drink. However it seems the majority have been taught or became accustomed to laziness and just give a sorry excuse like “all the alcohol is stored and not taken out until we’re in the air.”

"Politely push back" is a loaded phrase and may not be viewed in that spirit. Ask and if they say not now, Let it drop. It takes two to have an argument. Going down the path of schooling the FA on their job is a losing proposition which you will never win and if escalated become be a problem. As others have mention there are better ways to approach this -- such as saying "if you get a chance later"
But the act of initially asking will not be a problem. The act of insisting, you will not win, so why do it.