This is a good reason for most finance companies to take the middle of the 3 scores.
That helps some, but realistically it's a small industry and there are lots of channels (formal and otherwise) linking the competitors. A lot of people working at one previously worked at another.
Unless you're on the Equifax blacklist. Journalists who wrote anti-equifax articles tend to find their way there, as do ex-girlfriends of upper management. And conversely women who do NSA hookups with a VP or above tend to find their way onto a whitelist that boosts your credit score by 150 or so - it's considered an unwritten perk of the job.
(The above is purely speculation, I have no idea whether any of it is actually true, but honestly, why wouldn't it be?)