The most distracting sounds to me are hearing a page ripped out of a binder and a judge asking for the next dog's number before mine is back in from the field.
I have never recorded audio, & I'm probably focused too much, but I haven't "noticed" any excess noise. Judges I've had have been pretty good about reminding people about cell phones & gallery noise down. Sometimes I enjoy the judges who carry on a conversation with me. Like "what's he doing? He had to just step on it."
HR True Grits Finer Edge
Duckdog's Fast Autofocus
GMHRCH-III WR North Star's Deuce of Diamonds
MHR WR Pondview's Bar None 1994-2006
I know that if I were to chit chat with a judge that I will leave the line remembering every detail of the conversation and dogs performance secondarily: therefore, as a judge I don't talk to handlers, unless spoken to.