This...Racism is everywhere, it just is, that's a fact...SO
Always ask...NEVER assume, when it comes to issues of race, age or weight etc. Just because an ad doesn't mentions limitations or preferences, does not mean there aren't any. If it is an issue for you, it might be an issue for the escort, give the escort the opportunity to express limitations or preferences. I have in the past experienced numerous situations that became uncomfortable. All of which could have been avoided.
Now whether or not an escort should state limitations and or preferences in his ad upfront, is another whole argument.
p.s. I like your new avatar @Lab12