proposed rule - ties never lighter than shirt

Maybe this is covered by other would-be rules, but in the process of thinking about what to wear to an upcoming wedding, I stumbled across the idea that generally (perhaps frequently enough to be called a "rule"), wearing a tie that is lighter in color than the shirt with-which it is paired just looks bad.

I'm sure there must be exceptions, but I'm having trouble picturing any. (especially if one engages in the mental exercise of picturing the tie on a darker shirt, and then picturing the same tie on a lighter shirt). The closest thing to an exception I've come up with is a light yellow tie on a darker blue shirt - though here you probably need white cuffs/collar to make it look professional, and the tie probably would look better on a lighter blue shirt anyway...

Thoughts?

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cpac