Slightly off topic but I have been through security with a small victorinox penknife on my keyring on numerous occasions and only had it looked at once.
So why is it acceptable to carry a small knife on a plane that if I was so inclined I could easily stab or slash someone with, but I cannot carry a normal tube of toothpaste?
And on a recent journey to Majorca they lady in front of us had a couple of individual cartons of baby formula which are sealed to keep them sterile, the attendant made her open them and sip from each thus defeating the object of carrying the sterile formula for her baby,all seems a bit daft after my above statement.