Isn't etiquette a little bit like grammar? Do you have to follow the rules because they're written in golden letters, or is common sense more powerful?
When I'm invited, if I bring a bottle of wine and it doesn't match the food, it's just put aside until the next invitation, or for other people to share. Most of the time, it's drunk though, before, or after the meal.
But flowers are always appreciated by women, and they gladly turn a blind eye on outdated snobbish conventions...