Last year I even advised a guy not to leave his mini credit card on his keychain in plain view. I just look at these things for awareness, but there are many criminals praying on what we leave on our keychains. Many military and veterans where their "dog tags" on key chains.
As a vet I notice military issued "Dog Tags" instantly. I had a colleague leave his keys in a conference room. His military tags had the following information on them.
1. Full Name
2. Social Security Number
3. Allergic to Penicillin
I walked up to him in his cubicle and mentioned his allergy to him. Of course he was surprised I knew this detail. I then handed back his keys and pointed to the tag. A malicious person could have done far worse with this information. When trying to secure organizations and even our personal lives, we must think as the bad guy would think.