[rdl]

Not in the case where it is one fairly respected hiring manager calling another in a smallish industry. Not corporate HR (startups, not like HR is more than form filling).

It would be exceedingly difficult to successfully sue someone for failing to return a call or email from a random outsider. Plausible deniability.

This is also one of the cases where being part of a "mafia" is awesome -- you can actually call up and get unvarnished opinions, or at least, cagey "I don't think I would" "That might be difficult" etc.