it don't matter if you're black or white

Help me out here. I like to do laundry properly. I separate darks from lights, handwash anything that tells me to (by hand, in the sink, not on the machine's 'handwash' cycle) and follow instructions to a ridiculous degree.

But when you're sorting lights from darks and you have something that's black and white striped where does it go? Darks? Lights? Why must laundry mess with my head? Luckily, I'm eco-conscious and do all my loads with cold water so I don't need to worry about fading of dark colours, so I tend to throw stripey stuff in with the whites, as I presume that because it's been treated so the black on the actual garment won't bleed with the white on the actual garment all should be well. But c'mon, washing's meant to be a no-brainer - isn't it?

Oh, and yes, that is a pink washing machine. A pink Smeg washing machine. I think I died a little on the inside when I saw it - I thought my hankering for a green Smeg fridge was going to be the end of me - but this? Oh wouldn't washing be bliss...