Minor clarification: guest dress code. That "could be considered a costume" line is quite open to interpretation. . .
A couple years a go a gentleman who is also works as a “real bearded” Santa Claus was visiting Disney Land. As I understand it he was wearing some red, probably just shirt or pants. Not a Santa suit by any means just some Santa-ish colors. At some point it was reported he let out a traditional Ho Ho Ho for which he was asked to Immediately leave the park.