Have you guys actually ever seen these guys? I have and when you know what to look for, it's kind of obvious who they are. Here are the distinguishing traits, so you can see if you can see them.
1. Big men. (Not big as in fat, big as in muscular)
2. Completely Alone.
3. Standing or sitting in places that a normal guest might not sit or stand. (Example, standing right next to the bag check)
4. An Earpiece and a wire going into their shirt. (This is the most obvious sign.)
5. The same person is standing in the same place when you pass multiple times in one day, or when you come to the park on a completely different day.
6. While their clothes do blend in on first glance, on further inspection you will notice that they are genarally wearing a button up shirt and slacks. Even though they are supposed to look like they are not in a costume, they still meat all of Disney's dressing and grooming standards.
Every single time I go to the park, I see the same man standing next to the bag check area wearing an earpiece. He is usually wearing a button-up Hawaiian shirt and black slacks and black shoes.
There are probably some guards that are more conspicuous than this one and the other few that I have noticed, and the only reason this one sticks out in my mind is because I see him all the time. I suppose they would look like a dad waiting for his family to an average guest, but once you know exactly what to look for (especially the earpiece) you start to notice that all they are missing is the name tag.