> Concert tickets are almost certainly in the 'dinner reservation' category. They have no need to identify me for national security reasons

Admittedly I haven't been to many concerts, but 'national security reasons' seems like a reasonable rationale to me because a packed concert sounds like a great place to set off a suicide bomb vest for maximum impact. Have a cut-out who doesn't raise any red flags buy the ticket and hand it off to the person wearing the vest. No ID check? Mass panic ensues when the vest goes off, and people are hurt in the stampede for the exits even if the blast radius of the vest itself isn't all that large.

Lots of big venues have metal detectors or wands, which targets the right thing, instead of privacy.

Metal detectors or whatever other measures are a more direct solution