Colour-blind...
So I'm at this bus stop, waiting for a bus (as yer do), and I got chatting to this attractive young lady. We were just making typically British small-talk - about the weather (it had been all lovely, hot and sunny for a couple of weeks).
"I love it when it's like this and you get a chance to flake out in the garden - soak up a few rays. You look like you've been making the most of it."
She raised one eyebrow, "No - I'm always this colour."

For once, the fates intervened and snatched the shovel from me before I could compound matters by saying, "Sorry."

:-(
(minimalist ..., Fri 17 Aug 2012, 11:55, 6 replies)

you could have got out of this spot easily, by asking her to take off her top
(cs1ca, Fri 17 Aug 2012, 14:08, closed)

I'll remember that in future...
...though perhaps employ a modicum of subtlety:

leave an awkward pause, then say, "So I guess showing me your tits is out of the question?"

Do you think that would work?
(minimalist ..., Fri 17 Aug 2012, 15:06, closed)

'you've been making the most of it'
'I'm always this colour'
'I bet you've got lovely dark nipples'
(cs1ca, Fri 17 Aug 2012, 15:40, closed)

That shouldn't be a problem.
I'd just say "you're lucky most of us have to work at it". Frankly, as your title suggests, making such a remark means you've no racial stereotypes and take people as you find them. I would think it weird if someone with natural dark skin were offended that you didn't realise their "ethnicity".
(Me, I'm not... in any way intoxicated, Fri 17 Aug 2012, 14:27, closed)

That was my take on it...
..but what really burns me is that I so nearly said, "sorry" - which could be taken in two ways:

a) Sorry for not realising your ethnicity - perfectly acceptable.
b) Sorry you are ethnic - very very bad.

T.b.h. I don't think she was miffed that I hadn't noticed she was 'mixed race'; but I found the whole thing quite cringe-worthy.
(minimalist ..., Fri 17 Aug 2012, 14:59, closed)

Yeah, "Sorry." could certainly be very awkward.
It is a weird situation though so I can understand it feeling a bit tense.
(Me, I'm not... in any way intoxicated, Fri 17 Aug 2012, 16:51, closed)