One security agent at Frankfurt would not allow me to take my toothpaste through Schengen security. I had many hours until my flight so I took my luggage (and toothpaste) back to the non-Schengen area and waited until that security agent took a break and then went through security. From what I could tell she told other agents about me (she talked to them each in turn and pointed at me while talking). None of them fussed over my toothpaste when I went through. I and felt like I won the FU lottery.
I just don't carry a multi-tool any longer no matter how TSA safe it's supposed to be. It's not just the US though. I had one of those super cheap 2-part wine corkscrews (no foil cutter) confiscated in Spain.
You will never dodge the odd malicious gate agent.
We were late for a flight in the Philippines and the gate agent knew it. Told me all of my travel fishing gear was contraband - even the rod and reel. Straight up stole all my fishing gear figuring (correctly) it was worth less to me than making my flight.
The security agents took it out, unfolded the knife blade, discussed it a bit in German and handed it back to me.
"It's OK! It's just a little guy! Go ahead".