IT TAKES GUTS to live on the street and survive, and more than a few smarts. If you are the one who lives there, you try to stay warm, dry and find enough to eat. You move from sidewalk to sidewalk, dumpster to dumpster. It's a stressful life, and dangerous, because you never know who you'll run into. Is that person eating across the table from you homeless because of circumstances beyond their control, or because he is deranged and dangerous? If you're an alcoholic attorney or a semi-crazy old woman , you could find yourself in real trouble, because the man across from you at the burn barrel might be a killer - and insane on top of it. Even if you're not living on the street, but a First Responder designated by society to deal with the homeless, you, too, must be cautious. Will that seemingly harmless man be carrying a gun, or a knife, or a lead pipe? Watch your back.