Like Horn said, just don't play the role of victim. These folks, are predators. They will pick the easiest prey they can find. Don't go out drinking alone, ever. Keep your wits, keep mentally sharp. If you are alone, not much you can do against a pack or mob. Even two guys is too much for most of us, unless you are well trained in martial arts. Sometimes, you can do everything right, but just be at the wrong place at the wrong time. It's best to avoid crowds, if you can. Always "pie the corner" as they taught us in academy. This is where you give corners, especially dark alley corners, a lot of room...and as you use vectors, angles to keep from being surprised. We got so good, we'd see folks hiding behind a corner before they saw us. I do this all the time at night. Distance equals time. Each foot you have of room increases your time response. Pie the corner.