IRL, I'm pretty obnoxious and oblivious, so I would just go up to someone if I noticed them struggling. The thing is, I don't notice people a lot when I am out, 'cause I am usually preoccupied (okay, some people would call it ditsy and self-absorbed). Having said that, I still haven't approached a total stranger, but I do approach mamas that I don't know in some of my moms' groups and offer to help them.