Of course. Race, gender, disability, height, weight, age, beauty, and on and on and on. Most if not all prejudice can be described as signals, and most of the work of activists dealing with those issues is to get society to react to those signals in a way that's neutral rather than positive or negative. (Not all activists realize that, which is how you get some of the really crazy-looking ones, like feminists who freak out every time a male has more power in a given situation than a female does.)

And yes, I've seen more instances than I can count of people processing the signals and ignoring the message, or, more annoyingly, expecting me to do just that, and then blaming it on me when I don't understand them, or go do what they said instead of what they meant. I'd even go so far as to say that most of the time when someone's logic really doesn't make sense, they're not using the logic for logic, they're using it as a carrier for the signals, and hoping (or, assuming - I'm probably giving them too much credit if I imply that it's being done consciously) that you'll play along. In fact, there are times when that seems to be the most useful communication strategy, and it's one I've been working on learning for the last few months.