For example, I've been told by someone who lived there that in Ireland, everyone is classified as Catholic or Protestant-- even if they're Jewish.
Happily, there isn't anywhere near as much of that sort of thing now as there used to be.
Eyewitness testimony isn't reliable-- it degrades rapidly with time (significant fading in 20 minutes), is easily overridden by circumstances (people are apt to assume that the guilty person is in a line-up unless they're specifically told the guilty person might not be there-- there's a risk of saying the best match is it rather than looking for a genuinely satisfying match), cross-racial identification is less competent than within race identification[1], the presence of a weapon makes accurate identification less likely....
It goes on-- if you have any interest in this sort of thing, I recommend reading the whole article.
[1] I wonder if this has been tested in societies with different classification systems. For example, I've been told by someone who lived there that in Ireland, everyone is classified as Catholic or Protestant-- even if they're Jewish. Would Irish people have problems doing identification across the Catholic-Protestant line, even if all the people involved would be considered white in America and not set off the identification problem?