I was at EPCOT a few years back and Mickey, Minnie, and their friends came out dressed in holiday costumes. I was on my way to meet my family for lunch so I was alone. I wanted to snap pics of the characters. I was told by the CM's not to stand in line if I wanted pictures of the characters by themselves, because it threw off their counts for knowing when to close the line.
I wanted my pictures without anyone else, but other people, kids and adults ended up in a few, because the CM's work people through the process so fast there isn't much of a chance to get a shot with them alone.