It doesn't really seem to be implemented yet.
Quick story from Tuesday this week:
PVG-FRA, booked in H class, reserved and online checked in emergency exit with SEN number. Got to the check-in desk, they welcomed me "Mr. Vinonobile, you've been upgraded due to overbooking, not a single seat left in economy."
Got the C boarding pass, asked them to change the mileage credit to my UA 1K account (needs to be credited there for the company, SEN is my private card).
She grabbed my boarding pass, said "op-ups only for senators". I try to argue that I am a SEN, just can't credit this flight there. No way to convince her. She takes 5 minutes to clear me a middle seat in the back because 32b and all other exit seats have been given away. (given she op-uped a middle seat in the back, I tend to think that person wasn't a SEN, at least not one who knows to reserve seats in advance)
Now, despite the disappointment about the missed op-up, I know I have no claim on that. But what really pissed me off is that it also cost me my seat reservation - the only possible way a tall person can stand LH Y. I thought about just taking my OLCI print out ... but I didn't think any good would have come out of making a fuss in the plane and confusing an innocent (and happy) person in 32B.
Being a SEN doesn't get you anything, crediting to UA 1K in H class (not a bad one if one thinks in the new supposed hierarchies) doesn't get you anything either. Only gets you neck-pain and numb legs in the back of the plane.