It's not because of throwing them
it's because they present a risk in the event of an evacuation.

A bottle without a lid will crush when the crowd steps on it, but a bottle with a lid will roll and can result in people falling over, which in an emergency evacuation situation is generally considered a bad thing.

They're not just being petty.
(Bazongaloid, Thu 10 Feb 2011, 18:36, 2 replies)

Really?
He told me it was because he thought I would throw it. He's obviously not a qualified steward, and I'm going to report him. Another little victory: 2-0.
( Norbert Lightowler, Thu 10 Feb 2011, 19:06, closed)

I went to
a concert in Hyde Park, they confiscated a large bottle of coke in it's entirety.
Also told me it was because I might throw it at the stage. Geoff Capes couldn't have hurled it that far.
Of course, as you say, it's probably for safety in the event of an evacuation.
I'm sure it was nothing to do with the fact that once inside, I had to pay 7 quid for a bottle the size of which wouldn't look out of place being pissed in and presented to a doctor.
(dchurch bah, Thu 10 Feb 2011, 19:45, closed)

it would be nothing to do with that, i'm so sure...
and you'd be a damned fool and a communist to think otherwise...
ahem.
( blaireau69 , the Cumbrian Travis Bickle., Thu 10 Feb 2011, 22:06, closed)