Number one rule of hiring: take up references
I'd consider just a plain criminal background check, but for the rest of it, my credit is none of anybody's damn business. The demand to call all my previous employers and verify salaries is similarly horseshit -- my previous salaries don't matter a damn, all that matters is our agreement on what an employer is going to pay me. The weird thing is companies get indignant if you turn them down for this reason, and pissy when you characterize the demand for such a check as a lack of trust. Particularly since my previous 3 bosses are references. While I suppose someone could fake references, it's hard to do with linkedin, especially since someone doing a reference call to an arbitrary phone number could just ask for a verification email from corporate email.
It never really made a whole lot of sense to me, since most people in the tech industry in debt got that way through a failed startup, or maybe a divorce, or medical expenses, or something like that; none of which makes you a less good candidate. Maybe a lot of charge-offs would be an issue for a CFO.
My general philosophy on references is they only really count if they're strong mutually known parties; a random manager at IBM vouching for someone is pretty meaningless to me. The first circle is founders' personal contacts, then people introduced by their contacts, and people who are introduced by people known to early employees. That scales pretty far if you're hiring in a specific domain.
How would one phrase questions to get the true answers from references?
Seriously... I've found that people in sales are so used to bullshitting their way to a deal that you have to double and triple check everything in their backgrounds.