How do you tell someone their weave is falling out?

Today I was on my morning train to work...exciting as ever. On occasion early in the morning there are a few potential lol's, en route to Chicago. This morning I'm sitting there reading "Barefoot" (side note: good read), and a woman sits down in front of me...and I notice something falling out of her hair. But wait....that's not just anything...that is in fact her weave falling out!! Girl needs to get that checked, but should I have been courteous and mentioned her weave was falling out? "Hi, you don't know me but I was sitting behind you and girl your weave is falling out." Now the last thing I want is to get beat down on the morning commuter train. But I did feel a slight moral obligation to mention to the woman she should in fact check the back of her head/weave.