Every draft pick is a gamble in one way or another, but some selections are even riskier bets.
The media and fans call this concept "red flags." The jargon used by teams is often "significant character concerns" or "non-football issues." Every team is different in how they deal with problematic draft prospects, but each team is the same in sniffing out any potential issues with every single player on the board.
Private investigators are able to retire early in cities like College Station, Tex. and Tuscaloosa, Ala. because of the money NFL teams pay them to keep tabs on top prospects. Local scouts are kept on payrolls long after their player evaluations are given because of who they know on college campuses—janitors, trainers, boosters, landscapers, you name it. It's become a cottage industry because NFL teams want to make the smartest investment possible.
Of course, non-football issues might also mean a significant injury in someone's past—a blown-out knee or a torn shoulder muscle. Modern medicine makes some of this a moot point, but if all things are equal, teams will often take the player with a clean bill of health. At the very least, players with an injury-filled past are poked and prodded even more than the average prospect. No stone is left unturned.
This is also why prospects weigh in at the combine, Senior Bowl and Shrine Game wearing only their spandex. Not only does it give a more accurate measurement, but it also allows scouts to assess things like tattoos, piercings, surgical scars, extra flab, etc. This is physical evidence that sends the scouts scurrying to find out more.
So, where will the players with the most controversial stock land in this draft class?