This just happened a few days ago and my god do I feel vindicated.
I work as a corporate receptionnist, for a large office building. In my country we are still under quite strict anti-terrorism security measures. This means that in my building, you have to either have a corporate badge to go in or someone from the company you are visiting needs to come get you at reception (I can't even call some of them as they are self contained corporate offices, the visitor has to call whoever they're visiting themselves). I also work for the building and not for any of the corporations renting office space in the upper floors.
Yesterday a very neat and karen-type woman came in and asked to go up to one of the corporate floors. As she didn't work here, I told her that someone had to come get her. She started huffing and puffing and calling various people while complaining that "she never had to do this before" "it's ridiculous, I've already been here". No one would answer her calls and she got more and more worked up, berating me for my "ridiculous behaviour", telling me "you have no idea who I am" and screaming that I needed to let her in NOW and that she had A VERY IMPORTANT APPOINTMENT!
This escalated to the point where she basically tried to force her way in while I was threatening to call security. All this time I was basically reapeating "It's procedure m'am/I don't know who you are and I don't care/get away from the security doors m'am".
Someone from the office FINALLY came to get her and as she was led away upstairs she called me a string of insults and insisted that she would "escalate this to management" and that I needed to "be taught a lesson". To which I answered "Oh don't worry about it mam, I'm gonna escalate it myself".
Which I absolutely did, told everything to my boss in an email, noting that the person asked me to escalate this to my management. Now my boss isn't perfect in a lot of situations but he absolutely will not concede anything on security, and he assessed that I had absolutely done my job to the best I could have and was blameless in this situation. After watching the video, where she is clearly seen berating and insulting me while I keep calm they've decided to escalate the situation to the corporate management in question, telling them that she was barred from site and they needed to apologise to me for her behaviour.
I just got the email and not only did they apologise for her behaviour, they ended it by this absolutely delicious titbit : "the person in question was being considered for a position but this was retracted at this time for obvious reasons".
Me : 1, Karen : 0