. . because the expression "He's Scotch" as an idication of "thrift" has largely faded from American usage (though one of my clients, Thrifty Appliance Repair, does feature a Scot in a kilt as their mascot, it's a rather old business). Scots just aren't a significant eth over here any more.

Given the "incorrect" usage is archaic I'm not surprised it doesn't show up in so general a Google search, however here is "supporting documentation" from a more specific Google search for [link|http://www.mcn.org/c/irapilgrim/race02.html|"He's Scotch"] (third paragraph).