You need to keep an eye on your laptop. If you leave the house, make sure that the bag is closed all the way, zipped closed. It is easy for a thief to steal your laptop out of the bag on the street or subway if they can see them. Then, when you go into your day to ensure that you keep the strap over your shoulder against the side of you body. This makes it much harder for a thief to snatch from you. If you place it on the ground, while paying for coffee or at the airport ticket counterMake sure you place it between your legs and squeeze around the ankle.