What principle is being violated here? Other than "be kind"?

Select all items whose color has an "R" in it. You have 15 seconds left.

	One	Color	Size
	One	Red	2
	Two	Pink	34
	Three	Green	23
	Four	Suet	23
	Five	Norwegian Midwinter Sky	2
	Six	Sunny	4
	Seven	Maroon	3
	Eight	Furious Blush	267
	Nine	Rage	0
	Ten	Shame	3
	Eleven	Blue You Saw Once Before	34
	Twelve	Rainy Dawn
	Thirteen	Unsettling Hue	2
	Fourteen	Uncanny Tone	32
	Sixteen	Eldritch Fuschia	23
	Sixteen	Mellow Marygold	7