Were traps always like this?

I noticed something last night that I have never noticed before. Have traps always affected both your enemies AND you and your allies? I had gotten in the habit of planting traps under myself, pulling a mob with my longbow, then switching to a faster bow when they got close. The traps would go off, making my life that much easier. Did they change something? Or was I just getting lucky before? I planted both a dust trap and a barbed trap under myself as some Sand Giants were heading my way. When they got to me, the traps went off, and not only were the giants all blind and bleeding, but I was as well. Has it always been this way? Or did the traps get an "update"?

I think I found out what happened - if your traps go off because they have reached their time limit, then it affects anyone in it's radius - including yourself and your allies. Good thing to know.