ok, what's the deal

at every sporting event now, players and coaches are covering their mouths when they talk.

are there TONS of lip readers at every single solitary sporting event? are they really that effective? do they have walkie-talkies to the dugouts/sidelines/benches? are they watching the broadcast and phoning in their espionage?

seriously, does someone have some inside info? it seems a little overboard. even at the cutthroat pro level