To my experience this kind of gifts are used to open a subliminal door to the "victim", as you will be unconsciously grateful to the jew while wearing the bracelet regardless its origin. If this bracelet reminds you of something of your past (or even a past life) you may be unconsciously opening a door to this jew.
Also, bracelet at the arm put by someone else is a subliminal symbol for capturing the person wearing it.
I know I am a bit extreme on this, but excess defense is better than neglecting things.
I usually get rid of anything I receive from negative people, or people that I don't like or I do not want linked to my soul.