And then there's the regular crazy Swiftie fangirls who obnoxiously battle each other on Tumblr and concerts to get noticed by Taylor while despising all the people who have gotten picked to meet her. There have been numerous incidents at concerts of people jumping up on the stage and trying to grab her. I remember a few moments during the Reputation tour where she appeared very distracted between sets, snapping her head to the side as if she thought someone was about to jump her. I don't blame her for being paranoid, fans can be crazy.
I think also these big ticket venues are rightly more paranoid as of late, especially since Manchester and the shooting in LA. I made this really cool (I thought so at least) wearable LED matrix tee shirt (RGB Neopixels driven by a Teensyduino and cellphone battery pack) that displayed various Taylor related animations, but was only able to get it in 2 concerts out of uhm...several that I went to (Hackers can be Swifties too ok). The rules seemed arbitrary and highly dependent on what security guard you got when entering, which did not instill me with much confidence (one guard said the LED's were fine but I could not take the battery. Well ok then, even though the battery was just a regular cellphone charger that they explicitly did allow. And several times after I had been denied I go into the concert only to see other people with light up LED signs on full display).
Anyway, it's one thing for a private venue to employ these measures for security to voluntary participants who knew damn well they were surrounded by guards and had to abide by certain rules, and an entire other sinister thing for governments to arbitrarily collect this data on everyone to do god knows what with backed by the power of the state.
Between you know, John Lennon and the recent sad story of Christina Grimmie, I'm very glad Taylor Swift is taking security seriously.