That depends on who they are eg their age etc. If they are very old or very young, then they are vulnerable, so I would ask them, but otherwise I would act with caution ..............
if the person is alone, I would probably go to him/her.
Just walk away. Sometime people just need a a quiet moment. If they need a shoulder, most likely they would know what they need to do.
keep walking and ask if everything is ok
I doubt I would ask them.
A number of reasons....a couple being that they might be crazy as hell and other that they might be a scammer.
What should I do?