Very true. Is there a real biblical difference between what a servant is and a slave though?
That's an interesting question, one I don't have a ready answer for.
I imagine it would take a good understanding of the cultures and times involved to fully discern it, the lines between the two seem to be a bit blurred and not readily apparent as near as I can tell.
There are also different kinds of servitude in practice during biblical times as well and their relationship to a master in each of them. Maybe someone else could give a better answer than I can, but in any case they would all imply an unquestioned allegiance to the Master they serve.
An interesting topic to discuss.