I have seen a couple of girls looking stuck and helped them out. I made sure they took a picture of the reg and passed it on. To me it makes sense, increasing the chances of someone being found out makes them less likely to be a danger.
My pet hate is realising I am walking behind some girl who has started looking nervous. There is very little you can do to alleviate it. If you slow down it looks suspicious, and they don't want you near them so it is hard to walk past to get in front. It is a price most men face because of other people misgivings.