I'm actually alittle okay with locked backpacks, it sorta should stop players from killing random players for their loot and make decisions like "Would killing this guy and waiting 5-10mins be a good option or go on my way to find my own loot".
Just think of a pad lock on the backpack, it's not gonna take you 5 seconds to rip it open to get the contains inside. It would take time for you to gain access to the backpack to loot it, if you think waiting around would benefit you for that loot you just killed for. If you happen to have a lockpick you'd just bypass it all together.
I fail to understand this lock pick idea... I have a damn metal hatchet! Or even better a fucking M4 with 556 rounds that will turn that lock into dust!