Originally Posted by
yvrgary
Yeah, United FAs often have to manage this with a whip and a chair. Especially in the South, common to see every seat in Y full while Y+ sits mostly empty.
...guess they don't want people cheapening the Economy product!

I'll never forget my SDQ-EWR flight. It was exactly as described. EVERY seat behind E+ was taken. And everyone in E+ had a row or two to themselves.
But if you can get it free at the gate or check-in, there's no point in paying ahead of time. And if you can get it for free on board, there's still no point.
They need to enforce it as much as J if they want people to actually pay for it. However, they could do LMU offers at check-in for 50% off or something. So if your status entitles you to 50% off, then it would be free at check-in. But only if the loads warrant it (so if they know 20 people are going to have to end up in preferred seats, offer the LMU, otherwise, don't).