Hello everybody! I found a cute little trick you can do, which can be useful in WvW roaming or event farming. It lets you to set three extra traps, allowing you a total of 6 traps. All you'll need are at least 20 point into the skirmishing tree. In the first screen you can see I have three traps on the ground, Spike Trap, Snake Trap, and Fire Trap. After setting those down, you will want to open up your traits tree and change your master trait to "Trapper's Expertise" Doing this will essentially give you three new traps, ground targeted and larger radius ones. You may have noticed that these spells don't share a cooldown with your regular traps! Yes, that is all there is to the exploit. Set three traps, change traits, set the same three traps again!
I know it can be really annoying to switch your traits every time you want to do this, to combat this I dragged my trait window to the bottom left corner of my screen (refer to my last screenshot). You can move your chat window to the top left part of your screen if you don't like it being blocked. Using this method, I find it very easy to set all six traps in less than 5 seconds.
Have a nice day!