I would think pins would be a no-no...HOWEVER, the last couple times I flew I'm positive I had a few pins in my carryon. So I don't know how strict they are about this.
One thing I KNOW they don't allow......make sure you don't have a mini-Leatherman on your keychain!
OMG that was so embarrassing. The last time I flew, I forgot to take mine off my keychain and of course they swooped in on it. I was so embarrassed I started to cry! (Which was even more embarrassing.
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I was far too mortified to go back and check it...I just asked them to throw it away. LOL