People Asking for my Phone to Place a Call

Hi All, I have had this experience for an uncomfortable number of times now. Some random person walks up to me explaining a story why they don't have a phone with them and why I should help them place an urgent call with my phone. I am begining to think there is an ulterior motive behind this, for the number of times I have had such an experience does not speak of random events. Has anyone here had such experiences as well?