What a bunch of crap! They set meetings up for this stuff??!! "Borderline rude" and two people! They need to just throw this out of the window. The admin. apparently need to look busy if they persue this. I would not sign anything if they try to write you up on this.
A similar incident happened to me: I was taken aside by the guy in HR one day, and was told that a CNA I worked with didn't feel I was friendly as evidenced by me not hugging and kissing her upon arrival (This was in Miami, by the way, it's a latin thing...). I'm Puerto Rican, but I don't just go up to people, and do that either, I like my space. Maybe it was the way I looked at him after the last word came out of his mouth, but I think he realized how he sounded, and sheepishly said, "well just try to smile more". Wow. So don't worry, silly complaints happen all the time.