I would bet your Sister uses similar phrases about specific issues and topics that she has mastered.
I will give you an example.
Around 20 years ago, I bought some memory sticks for almost nothing, mainly because it was out of date. It came with a short, maybe 5 minute VHS tape telling you how to install it and showing how you should use a device on your wrist to cancel static electricity.
I had purchased maybe a half dozen of those memory chips and had the same number of tapes. I needed to send her a couple of very short video shots and used one of those throw away tapes to record the maybe 10 seconds.
Well she would tell everyone that she was a computer genius and worked for the local college’s computer lab. Now she may have actually worked for the college but knew almost nothing about computers.
One day some guy was installing some RAM (newer and of a type which did not require you to ground your wrist.
Well my Sister promptly tells him that he should not install it unless he had the proper grounding device.
I knew exactly where she had gotten that bit of info. It was on that cheap VHS tape I had sent her. In a way I guess the ability to fool people takes some intelligence but it mainly takes someone who is brazen.