The only 'rules' that I think should be followed:

That the color choices look good to the maker and are appropriate for the purpose.

I've heard the black & white one, bits of yellow one, and bits of red one....... I think it's quilt police......

I say make quilts in the colors that YOU choose, and make you happy! Do what your heart desires~~

When they say black and white they may be referring to value. Value is the degree of light or dark to a color. All quilts are improved with value changes. Light, Med, Dark and everything in between. The value scale has 10 steps from black to white. For ideas look at the paint isle in your local stores, each color that they show they then have at least 6 different values of that same color. When ever value changes are added to a color scheme in a quilt they go from nice to WOW. I challenge you to try it.

When the quilt police start paying for your fabric, supplies, talents and time, they can dictate what does or does not go into your quilts. 'til then, .......

I figure it's my quilt and I will put what fabrics and colors I want to put in it. Don't pay a bit of attention to the QP!

You want contrast, but it does not have to be black or white. I have a quilt right now that is various shades of rust/reds with a offwhite/ecru as the contrast. And even the contrast depends on what you want to achieve with your design. My quilt has a star in the center, and is made up of mostly half square triangles...I want a lot of contrast.
If I were doing a quilt that was a landscape, or art quilt depending on various shades of color (think going from sky to water to grass)...then I'd want a very minute change of color, and not a lot of contrast.

There are as many ways to make a quilt, as there are quilter's out there...do what pleases you.

Heard that Log Cabin center block should be red, but that's another rule to be bent. Do what you like and let others have something to complain about :p.

Bologna-- I make quilts to please me. This is why I don't join any groups, guilds or swap or try to sell quilts. I don't want anyone's opinion or ideas for my quilts. I'm hard enough on myself, don't need any help.

Another silly rule to be broken:)

My thoughts exactly. Just question, though.