Here is a link to the NFHS - Instructions to Scorers and Timers
http://www.nfhs.org/core/contentmana...rerstimers.pdf
Clearly the Table Crew (usually also part of the Home Team) overstepped their authority. The home team received an unintended benefit of having the game at home.
If the officials recognize the horn, the home team has clearly benefited from the stoppage in play. They have an opportunity to communicate enough to set up an offensive or defensive play. At that point, is it an inadvertant whistle? Now the coach is asking for the TO and if the officials do not recognize it they will have other problems with whoever their assigning authority is. Damned if you do, damned it you don't now.