[neilv]

I like karma, but wouldn't checking have the appearance of illegal collusion between the companies? For example, would it look like they were price-fixing?

"Oh, your honor, I was only checking whether they had an offer. We totally weren't discussing how we'd not raise our offers, with the goal of suppressing wages."

[hyperadvanced]

iirc there’s already an app for that in some sense, and a good amount of plausible deniability and backroom politics that can make up for any potential lawsuit. Similar issue to “proving” any kind of discrimination: a smooth corporate operator can CYA well enough to create a fake paper trail to justify any sort of decision making.

[ghaff]

I mean, that sounds like a level of due dilegence that a lot of companies are unlikely to follow. I suspect that most don't even check the references that you give them.