I dont think they train them, at DL, for that anymore. I've seen plenty that look different from the "same" character.
When we stayed at PP in Oct (conc. level) I called in advance and asked for pictures and balloons. There were none when we checked in. I asked the conc. hostess the next day. She said they would be there when we returned that day. Still nothing. Finally on day three she gave me their pic's when we came into the lounge. We never did get balloons. We chatted with the cm for a few minutes about getting them autographed (the kids were not around). She admitted that she signed them all- Snow White, Belle, Cinderella, Buzz, Woody, Jessie, etc. She was a princess at one time, before working at PP. She couldn't tell us which one.