After reading these comments, I am beginning to think it's a combination of 2 things. With a dash of, only happening, or only noticeable, on certain routes.

1. Capacity Control
2. Pushing E+

My reasoning:

1: Capacity Control
One of my flights last Thursday (CR7) was totally full in E+ when I checked at the upgrade windows. When I checked in on-line at exactly 24 hours, bada bing, seats in E+. Random patterns of seats together as well. All 4 bulk head seats, and a one random block of two. It reminded me of when I look at a flight 6 months out not logged in, and then log in and look at the same flight. While not logged in, random blocks of seats show as occupied. When I log in, everything is open. (Or at least it used to be that way).

So, my logic tells me that they blocked 6 seats until the 24 hour mark so they could sell it at OLCI. (Maybe more).

2: Up Selling

• The chickens now wear a wrap talking about E+
• E+ Commercials
• E+ Ads on news websites
• Facebook: "Extra space onboard is always appreciated, right? That's why we offer you Economy Plus and why we are having a Personal Space Sale! Get more legroom for less through August 27."

My further (funny) reasoning:
Two guys were in front of me at the chicken (Yes, I prefer a boarding card to a print out). They paid to move to E+, and were across the aisle from me. After sitting they complained to the FA that they paid to UG to F, and that they showed them the receipt, she told them they paid to "upgrade" to economy plus. The whole flight they complained about how they were ripped off and this was still coach. No where in anyway did the Chicken imply they were paying for F.

Now I must state, so I don't get flamed, this is only based on my recent experiences on certain routes. So I could be totally wrong. And I am happy that UA is selling this, but also frustrated, which is why I have 3 trips booked on F9 in the near future, and paid for their version of E+. Strangely enough the F9 with stretch seating is cheaper than my UA flights. And I feel dirty being disloyal to UA. I promise to stay with UA when I can get E+.