They might use a knife to cut open the bottom of your backpack or bag and steal the contents without your knowledge. Don't give money to panhandlers. There are public agencies and charities that provide food, shelter, and job assistance to the poor. A panhandler will probably spend the money on alcohol and illegal drugs. Most likely their appearance and story is a carefully contrived lie.
Panhandlers often collect several hundred dollars a day from gullible students.
Pocketbooks should have a strong strap and be worn across the front of the body, not over a shoulder. At the airport, use a luggage cart if you are having trouble managing your bags. Hold onto your bags tightly. Keep photocopies of important documents at home, since this will make it easier to replace them if they are lost or stolen. Keep some money separate from your purse or wallet to use in an emergency or if your other money is stolen.