If you don't have relock find a hard lock with a key that you can lock back. There are different fail echos, you want the one that implies that you failed to pick, not the one that is 'beyond your ability'. Find a lock that you can pick with a decent pick, but fail with shitty picks (Glinar). Elemental Temple has two, Seantryn Palace has two or three, probably footlocker, etc. Think about chests/doors that actually have things inside.