Since when is showing one's friends your aircraft not a valid reason? What sort of police state are you living in when an innocent act such as that is deemed to be a terrorist act? Because that's the implicit assumption in dissallowing the activity. What next? Showing off your new sports car isn't allowed because your friends might consider using it as a get away vehicle?
And just what does showing an ID achieve on it own? Proving that you are 'you' doesn't enhance security if that's all that happens. So, someone looks at whatever the ID is, agrees you're 'you' and..........then what? Does the checker have a black list of nefarious baddies that they use to compare to your name? No, of course not. Nor do they have the opposite - a white list. That would be even more cumbersome and, once hacked, gives serious bad guys a great way to pass through the system relatively unaccosted (but doesn't stop the UK gov. trying to implement one anyway with its ID card
).
Indeed, whitelists & blacklists don't even have to be hacked. They can be subverted by gaming the system. Send enough lackies through - especially sleepers or new recruits who have never previously meritted the blacklist - and you'll soon have a whitelisted cadre who are then deemed to be 'OK'. Until proven otherwise, of course, but hindsight won't be able to prevent the history they make. Have enough cannon fodder and you can even probe the security system with the whitelisted minions to find what equipment can be passed through and/or where the likelyhood of getting caught is the least.
By the way, none of this
apparent Fort Knox-ian** security system prevents someone using wire clippers in some dark corner of the airfield and crawling across the grass until they're in a suitable place to walk around as if they belong there with their laser printed fake airport ID boldly on display.
I can think of even easier ways to circumvent this security theatre so no doubt those with nefarious intent and resources are equally capable. Just because they're nasty doesn't mean they're stupid.
**
If Will S. could invent words then so can I 