This article explains laws with regards to recording live performances, the most important excerpt from this article explains what is legal vs what is practiced:
“Taping a portion of a show for your personal use is almost certainly fair use. Except, since everyone realizes that stopping the taping is much much easier than pulling down videos from the internet, the venue might confiscate your phone until the end of the show or shorten your night by throwing you out of the show. Both of which they can do.”
So the confiscation of recording devices is more of a safety precaution than a legal necessity. If clips are short and used for personal use, there is no violation of copyright.
I think confiscating recording devices is an extreme measure but I can see why some venues/artists may need to do so. If a performance requests not to be taped in the first place, I can understand a person doing so being kicked out. otherwise, I think that is too extreme and that it is unfair to immediately expect someone to misuse their recording.
I think this type of law is completely fair. Live performances make money because they are visual experiences. If audience members put that content online, future customers may not feel the need to pay for the experience if they can see the same thing online for free.
I think that although this precautionary measure certainly makes sense, it seems a little too extreme to me. Although it is understandable that artists want to ensure that their work won’t be posted on the internet, I don’t think that they should have the right to have so much control over whether or not an individual carries recording devices on them.