A suggestion;

You might point out to him that a plain Khaki Freedom Kilt is PERFECT to wear with tartan shirts, Hawaiian shirts, tartan vests, tartan ties. Plain kilts are kinda like plain pants...they're there and let the rest of the wardrobe shine.

Or, you could remind/show him that most kilt addicts have and wear BOTH tartan kilts and plain kilts.

I'm also on the side of the "take the money and run" folks. Why look a gift kilt in the mouth??

Ron