Back in the the before times of the '90's, when it still existed, I flew on SwissAir in a premium cabin for work; they gave all the passengers Swiss Army knives as a gift while we were in the air...
You can fly with a swiss army knife in europe, or at least nobody ever questioned me. If you buy local everywhere you fly look for opinels, for $10 you get the perfect camping/food knife
And throw it away every time? Or at least give it away or so?
Leave it at the hotel/hostel. I leave a small note so the cleaning staff knows it’s abandoned, not lost and in need of return.
I’ve done this with various things I forgot, like a phone charger for the local outlet type.