"It would be very risky to operate, even briefly, a portable imsi catcher in a briefcase and move it around WA DC, nevermind one that remained in fixed locations for hours."

Even more so in 2018 where an IMSI catcher is only relevant/useful if you downgrade the target to 2G operation, which requires some kind of additional interference/jamming.

Unless they are using "stingray" as some kind of generic term for "device you use to intercept mobile phones" and there are now 3G/LTE "stingrays".

This would all be so simple to deal with if phones just displayed an "unlocked" or "downgraded" warning when operating in 2G or unencrypted mode ...