Drop It

In a recent profile of Amy Adams, New York Times critic Manohla Dargis noted the actress could cry "at the drop of a dime."

That's not right, is it?

You do things at the drop of a hat.  And if you want to snitch on someone, you drop a dime on them (which I assume means calling the cops, or something like that).  Or you can stop on a dime.

How did this get through all those layers of checks and balances?

PS  I've checked, and apparently some people do use this locution, though it seems to have been coined (as it were) fairly recently.  It's likely a confusion of other phrases.