This just happened to me about 2 weeks ago. I have a monthly pass, but I forgot to grab my wallet before leaving for work (Actually, I grabbed the wrong wallet). When the conductor came to me, I explained that I had a monthly pass but forgot it. He said he could not help me out and asked me to pay. I further explained that I forgot my wallet and had no money either. He asked if I had a photo ID, which I did not. He said I would need to fill out a form. He shuffled through his papers for a second, and then told me he would be back with the form. He never came back. I took this as him letting me slide but not wanting everyone around me to know he was letting me slide. I thought it was very nice of him.