That's true! That was the one included safety device I used right before cutting off my finger tip.

that's what the cowboy hat is for

Tbf with many mandolins those things are utter garbage especially if you need to go fast, not waste 20% of your food, and aren’t into dulling the blades when you slam metal prongs into them which is 40% of why you never see professional chefs use the guard in videos (the other 60% being “I’m a super cool chef” bullshit which is why they also never wear the protective gloves either

Nor do I. It wasn't for me.

However, I was unfamiliar with its operation. There was a guard, which I did use; but apparently it was supposed to interface with rails, which I didn't know about or use. Also it's commonly used with blade resistant gloves, which I didn't even own at the time.

So yes, it's a potentially dangerous device, but there are ways to make it less so.