It is the moment every Wimbledon leap-reader waits for - when a player forgets to raise his hand to cover his mouth when making a comment to his doubles partner.
So rare are such events, many doubles partnerships are terminating contracts with the lip-readers in their entourages, as they can no longer justify the expense of retaining their services.
But the lure of an unguarded insight into your opponents' strategy remains strong in the world of professional doubles tennis, so for now, the job of the lip-reading tennis snoop remains safe.
But new technology could mean their jobs are threatened after all, as more players grow lush moustaches to conceal their lips, learn ventriloquism or pay to have their faces pixelated during matches.
The annual cold war in SW19 goes on, with the real possibility that there will be no winners in the end, except perhaps the pair that lift the trophy this Sunday.