Haven't posted a simple link to a news article in quite some time, but I found this one really interesting. I have of course written a decent amount of posts on the question of race in the United States here, one very positive, others more negative (1, 2, 3, 4) plus a variety of book reviews (1, 2, 3, 4). The article deals with Obama's impact on social interracial relations in the US:
Two studies on strategic colorblindness [...] concluded that whites, including children as young as 10, may attempt to avoid talking about race with blacks, or even acknowledging racial differences, so as not to appear prejudiced.
The studies also found that blacks viewed that tactic as evidence of prejudice.
I don't luckily have that kind of sensitivity, timidity or whatever you might call it. Maybe always being the foreigner helps, in any case I never encountered a negative response to my curious question or remarks.