People who stay in specific areas and wait for targets to come to them. Though when you have a long-range weapon like a Sniper Rifle, a target 'coming to you' can be from literally across the map; so long as they're in your sight lines. It's why camping with a Sniper Rifle, to people with at least half a brain, is fine. They're not intended to be close-range weapons but Call of Duty's quickscoping fad has warped the role of Sniper Rifles into some "rush" weapon.