Next time you are at the enemy flag and you are alone (no resistance) pick up their flag, drop, pickup , drop as fast as you can. Most time it will duplicate into 2 flags. Also works if you are stuck in a hunter ice trap at their flag. When it does dupe, once someone picks it up, there will still be a second flag there for your team to grab.
Again, spam the drop and pickup as fast as you can. (right click the flag 'buff' to drop)
Again, spam the drop and pickup as fast as you can. (right click the flag 'buff' to drop)