You know this, right?
When someone calls you up for a reference check and you do anything short of saying they're unbelievable (they provided your name after all), it's not being borderline neutral.
Neutral is the new negative with reference checks. And it's been that way for awhile.
Think about that when someone calls you, and you say you can only give name, rank and serial number on a candidate who used you for a reference.
PS - A reference checker's ability to get any type of true negative information out of a reference is gold. Try my favorite reference checking question below to get a negative view:
"What job in your organization would you not put this person into under any circumstances? Why?"
It's up with people day here at the Capitalist. Go extract some negative info when checking references - just for the contrast and actually learning something you didn't know about the candidate.