I was a venue technology manager for the Vancouver 2010 Winter Olympics. I can't speak for everything regarding how wireless communication tools were used, but anything that was scoring-related, application-related, or PC-related had to run on hard network lines. Wifi was deemed too risky for ensuring connectivity, even on non-Games-critical systems and processes. We had only a couple of exceptions (example: every venue had an Athlete's Lounge, and every Athlete's Lounge had wifi for the athletes). I could be wrong, but I don't believe wifi was allowed for any operations-related purposes.

We literally dug trenches in concrete and in mountainsides to lay fibre and copper, rather than rely on wifi, even where there were concentrated temporary buildings or trailers at outdoor venues.

The only valid uses for wireless that I recall were radios for security and general Games operations (security and general operations had different spectrum, if I recall, with the general operations being further separated into different bandings, depending on the type of operations), plus mobile phones.

I'm sure there were various other wireless communication tools. For example, in rare cases where there was no way to get coax somewhere for TV screens (i.e. like the top of a mountain), we installed satellite dishes instead, after making sure that line of sight was OK. But although I can't think of much else, I'm sure there were plenty. I regularly spoke with the Games spectrum manager about setting up his infrastructure requirements, as they were going to set up operations at each venue for monitoring the airwaves and detecting rogue signals, or overreaching signals. It wasn't simply some man walking around with some device. It was pretty heavy-duty equipment.

But to be clear, things like referring and planning, I can't imagine relying on wireless communication tools all that much, if at all. Especially timing and scoring. The timing and scoring requirements were the most mission-critical stuff. I've never been treated like shit as much as the Omega guys treated me because we weren't finished their photo-finish stuff by the time they arrived, though we were of course ready by opening day.

edit: OK, if I recall, the broadcasters may have wanted spectrum for their own uses. And the press tents definitely all had wireless for the journalists and photographers also. But nothing else crosses my mind. Here's another example how important it was to have the hard lines. We dug trenches all the way up Whistler Creekside to lay down the fibre and timing cables for the alpine skiing course. This way, photographers could take photos of the racers, jack into the fibre via some mobile sheltered switches (they were on modified sleds) we set up on the course, and the photos would arrive down at the bottom for editing and collating before the racers reached the bottom. That way as soon as a result was announced, any newspaper/sports/etc website could put up their article with photo almost instantaneously after the racer finished. That would not have been possible with wireless.

edit2: Sorry, reading this, I realize it's not very well written. Points all over the place, nothing in order. Sorry, guess I'll just leave it as it is.