I wish they were consistent about keeping the drunks off. I used to be a regular on a US SFO-CLT Sunday night redeye. I would have a couple beers before takeoff and sleep all the way to CLT. One night a guy on the stool next to me was buying drinks for everyone in the bar (4 of us) and consuming way too many double Manhattans.

An hour into the flight an FA asked me if I'd mind a seatmate. Apparently, "my buddy from the bar" had been harassing his seatmate. 15 minutes later, he was back in his old seat and getting a serious lecture from the co-pilot. By the time we landed, he had kicked a FA. He was on his cell phone with his lawyer (at 6 a.m.) when the marshalls dragged him off the plane.

He got his wake-up call but seems like there's a couple more - not as extreme - but still drunk enough to be obnoxious, on every other flight I'm on. The later in the evening, the worse it gets.