This is an interesting point but staff clearly still have access to phones and could make emergency calls if necessary. And it’s a bit of a straw man argument as this was never seen as a huge emergency concern before the invention of the smartphone, as there have been thousands of shows up to the 90s that kicked off without any problems or emergencies. Clearly having the ability to tweet or call 911 is not the panacea for terrorist activity at concert venues – there are far better and more direct solutions to these problems that we needn’t get into. Citing security threats is the same argument people use for carrying concealed weapons to places where they seem unnecessary. The point here is not to take away people’s freedom to Instagram, it’s to ensure a better performance and experience for all attendees.