Plenty of other live events have policies against recording and cell phone use and don't seem to have any serious problems enforcing those policies (or, indeed, need to do much "enforcement" at all). Perhaps rock concerts are different because of the type of crowd.
Sure, cell phones can contribute to personal safety; whether it actually does in a standing-room-only rock concert given the distribution of risks one is likely to encounter in that context is another matter. I have a hard time imagining one, except a medical emergency, maybe? Except that having people find security might truly be more expedient.
Besides, I cam imagine real harm. Everyone simultaneously receiving a false alarm that a ballistic missile is headed there way might actually cause Widespread Panic to come out and play an encore.
Someone mentioned above that, in the event of a fire alarm and being separated from your group, being able to reconnect with them is important. Particularly for vulnerable people (whether due to age, health reasons, or being someone who might be targeted for violence or harassment), being separated from your group for a long time can be a safety issue.
being able to reconnect with them is important
As I mentioned in another comment, it's possible you've never taken someone with a disability or social dysfunction to their first-ever concert, knowing that it's partly enabled by the fact that you can easily reconnect if you get separated (by the crowd, bathroom lines, a fire alarm, etc.) Take away that extra measure of safety and security, and the majority of people can "just deal with it", but people with certain disabilities or vulnerabilities are going to have to opt out.
Personally, I'd rather work to be inclusive. Use social norms, not technological lockouts, to get people to put their phones away.
In one case, I leave the facility, get to safety, and then _go home_ (eventually), at which point I have my phone.
In the other case, I leave the facility, get to safety, but my phone is either destroyed, or in a pile with 900 other concert-goers' phones, and I need to either wait around (in a place where emergency services probably don't want extra people), or _replace my destroyed phone_.
No thanks, I'll keep my phone in my pocket or backpack, and have it with me when I leave with no extra effort. If necessary, this will mean skipping any concerts or similar where that's an issue.
You should check out how Yondr works: https://www.overyondr.com/howitworks/
The phone stays with you.
There are many situations where a cell phone can allow you to send or receive information that could tip the scales in your favor.
Does it still sound like hollywood?
Or, perhaps, some people are truly terrified to be away from their smartphones. That is itself a scary thought.
If a person's smartphone is removed from the picture for some reason, how would they be able to function? If the cell network went down, would the crowd descend into mindless chaos? There are no more pay phones, no more cozy landlines, so how would people manage if there were an emergency?
I get the point you're trying to make, but to me this just reads like gatekeeping.
Cell phones are useful and they can make people safer. In a world with cell phones not having timely access to one is riskier. In a world without cell phones it's a moot point.
The more interesting issue -- which others in this thread are discussing -- is whether the benefits of having a cell phone outweigh the harms people can cause with them, and whether policy can help strike an appropriate balance.