As a former resident of Robbinsdale, I still find it amusing whenever the town is mentioned in the news for reasons other than being the location of North Memorial Hospital, to where the latest north Minneapolis shooting victim was taken.
http://kstp.com/news/stories/S3371698.shtml
This cop didn't seem to have all of his "OPSEC" facilties about him. For example, as a cop who has probably overseen stings such as the one that got him, he knows that if you set an ambush for someone to capture them, you do it in a place of your choosing so you can control as many variables as possible. You get your mark to come to you, not you go to them, if you can avoid it.
If he wanted to engage in this activity without fear of being caught, he should have at least made arrangements to meet in a neutral third location of his choosing. If you are going somewhere they choose, there's always a chance it's a trap.
Applicable in many facets of life. I'm pretty sure I remember reading something about this in the writings of Sun Tzu.