I've brought a laptop to almost every event I've gone to and I've never had it stolen. If you leave it alone in the stands to go get lunch or something as a scout, just ask one of the teams near you to keep an eye on your stuff just in case. We always do that when we leave camera's and stuff in plain sight if we don't have someone to sit with them. I know any team that sits near me can feel free to ask me to watch their stuff while I'm scouting. If you're doing that job, just ask people not wearing that team's shirt to stay away from that area. -shrug- but then I'm paranoid.
