Is it tacky and potentially greedy? I'd say so. Is it theft? Not so much, in my opinion. Some things, like crisps, cookies, water, and coffee/tea, are meant to be taken away. As another poster mentioned, BA can institute a no-takeaway policy or place small placards at the water bar if they wish for people to consume in the lounge only. BA likely won't do this if it sees its customers as adults, but it's always an option if water "spillage" becomes an issue for them.

Last year, I watched someone fill a large Nalgene bottle with Johnny Walker Blue, plonk the empty JW bottle back on the bar, and then leave the lounge. That's abuse if I've ever seen it. I've seen plenty of people funneling "roadie" cocktails into smaller water bottles, too.

I lol'd. Maybe it's the dude selling blankets.