Wandering far from home

Being in college, I have sadly witnessed my fair share of drunken messes walking up and down high street or various other streets off campus. Heck, there are even girls and boys in my dorm who come back drunk out of their minds after a long night. Am I a bystander for not helping them home or helping them get back to their dorm rooms safely? I don't know. Maybe that is my responsibility, maybe it's not.
One particular situation that took place recently was at my sororities nacho night last week. My job was to stand in front of our house and let people know about our fundraiser. As our event came to a close, my sisters and I noticed a girl stumbling up the sidewalk towards us by herself. As she came up to us, I asked her if she was ok. She said yes, obviously she was fine (she was wasted out of her mind). Then she proceeded to ask where 12th avenue was. I pointed south because we were on 15th at the time and told her it was three blocks in the direction from which she just came. She begged to differ though. She was convinced that it was the way she was headed. After a few minutes of telling her otherwise she started going off about how she'd been walking this way for an hour and how she was going the wrong way all along. I knew she needed help getting back home and told her I'd walk her back but she insisted that she would be fine.
Later that night (and to this day, in fact), I wondered if she ever made it back ok or not. I still regret not walking her back and wish I would've gone with her or at least followed behind her until she made it back (is that creepy?!). All I know is that if I were in that type of situation, I surely hope someone would have the decency to help me home; and hope to God that it was a good person.
At the end of the day, it's in the past and there's nothing I can do about it now. I have learned from that situation however and know how the guilt of letting that girl wander off by herself to drunkenly find her way home has impacted me. I hope that next time I will be a better individual and peer and help someone who is so clearly in need.