My two cents only...
Common courtesy? Sure. Respect MUST be earned? Questionable. But as a buddhist and in my daily affirmations, I hold essentially an attitude of respect and reverence towards my fellow men. Buddhism transformed the idea of respect and obedience into a universal morality which protects the weak from the strong, which provides common models, standards, and rules, and which safeguards the growth of the individual. It is what makes liberty and equality effective.
I think that the idea of respect has been bastardized in today's culture. Machoism and popular culture are in part to blame. To me, respect is a courteous attitude of admiration or esteem for another. I can not possibly know everything there is to know about another human being - but I am certain they have endured tribulations, pain, suffering, but also have prevailed in personal matters and thrive for the common goal of happiness. To me, that is enough to respect my fellow man until their actions toward me give me reason to no longer have that respect. it is a mental attitude that I derive benefit from, as well as an action that nurtures tolerance, self-respect, esteem, and harmony.