The information stored in your license barcode is actually scary (I hosted a system for short while until the security company kept complaining the industrial wifi kept not working and *random moans*). Not happy with the closed wifi, they say ok, they'll host and back to they need wifi again, with internet... for free. No. I know what sites the guards visit at 2AM when hovering around the public wifi area -- could you imagine...
I have long been booted off that security committee, because I kept saying no X security company, you can't have internet (for free) and why do you need to scan licenses. The excuse was because the baddies won't use a fake (if the decryption keys are publicly available [else their scanners wouldn't work] then not impossible to make a new private key that works) or stolen license card. Sure Jan, sure...
Reality: the guy scanning is probably a grade D or C (look up their salaries on PSiRA and a big chunk is deducted for stuff) and mostly DGAF. The security company area reps usually give me a queazy feeling (say a lot then the backend staff enforce the opposite), but mostly I suspect a fair chunk of them sell data.
Then there is the frustration levels: guards that believe they are the law and get all iffy if your license disc/card is expired and demand the current card (I display an old one with some old data) before letting you out. Nevermind that a lot of people have to hunt for their license (ladies often get out the car, gingerly hop around on heels that could kill, open the boot, dig...dig some more... vibrating and shaking... found it...gingerly slink back). In short, the scanning process is a more than a few seconds to the better part of minutes, and compounded during rush hours. I have been to complexes/estates that all but want the dna report of your 2nd born, the milkman and a commissioner of oafs stamped declaration. Just doesn't jive with my colander headgear.
GOOD NEWS though
I have seen a few places with newer systems: stare at a camera and shake head (seems to do a liveness check) with ANPR in front, then the spikes go down and the boom goes up... time to use launch control and off to the races. Sure fake plates are an obvious thing, but the trick is slowing down the stolen vehicle with a trunk full of weapons from getting back out and get a nice pic of them smiling first. Ohh, and fewer smacked down gooseneck polls with the non-touch sensors that don't like you in particular.
Security theater vs inconspicuously engineered.