If the blade is under 3" and isn't a locking blade you don't need a reason. If the blade is longer than 3" you need a reason. "I'm taking this bottle of wine to

If the blade is under 3" and isn't a locking blade you don't need a reason. If the blade is longer than 3" you need a reason. "I'm taking this bottle of wine to my friend's house and they don't have a corkscrew" would be fine.