Spotters etc
I would have thought anything that leads to people being stood around near airports, for what ever reason would add to security risk, and the more of them ''authorised'' would lead to a complacency assessment build up.
A ''spotter'' stood at a perimeter fence with a long lense camera one day could be stood there with a surface to air device the next.
This is obviously a extreme scenario , but I hope you get my drift ?