My PIN

I wanted to reserve a book
But I forgot my PIN.
The library reserving site
Just would not let me in.

I typed my bar code, typed my name,
Gave several PINS a try;
But every one I entered
Simply would not satisfy.

I finally gave in and called;
A human did reset it.
I gave some numbers on the phone
But really, I don’t get it.

If PINS are such a secret,
Why was I allowed to share
My new number with a stranger?
That seems weird beyond compare.

Still, he helped me to reserve my book,
So now I can begin
To remember my new number
Next time I am asked my PIN.