Originally posted by nahouw
But then again, something has to be said about the object of his PA announcement -- why did that person not heed the announcement to begin with?
Probably because that person might not have even been in an area where fencing was actually occurring. At Nationals (I forget if it was at Greenville or Sacramento) George K. was singling out people that weren't even near strips that were being fenced on. I remember him singling out a guy in one of the enclosed areas that had maybe 4 strips being used (this was towards the latter part of a day, when things were starting to die down a bit; after a few rounds of DE's). That's 4 out of, like, 20! Who cares if there's a non-fencer in that area? Unless he was "streaking" through the enclosure, I sincerely doubt he was interfering with the good working order of those strips.

Originally posted by nahouw
And another question is for the referee on that strip -- he certainly had to hear George K.'s initial announcement -- why didn't he enforce the rule to maintain good order on his strip?
Probably because he didn't care that there were people in the fencing area. Many refs don't mind having people sitting near the strip, as long as they're not physically in their way and maintain a respectful noise level. I myself don't even notice most spectators until one of them happens to almost walk in front of me while directing. In that case, I just hold out an arm and stop them from walking in front of me and, politely but sternly, tell them to not walk between me and the strip. I don't have to stop the fencing to do this. I don't have to throw cards either. Most fencing spectators that do these relatively minor infractions are poorly informed about strip etiquette. If bout committees, refs, and fencers take the time to inform spectators about proper etiquette, they won't be a problem at all and no barriers will be needed to control them. Also, having good spectator traffic areas at the venues will limit the number of spectators that cut through the fencing areas to get from one side of the venue to the other.