I think there are two things that need to be separated out here:

1) Role play
2) Long distance M/s relationships.

I think what much of what denu is trying to reference falls under the first category, where role playing a slave does not make you one.

The second category is much more tricky, as people have stated, including myself, slavery is much more about a mindset than anything else. Now while this mindset is achievable through a long distance relationship, coming from the point of view of someone who has done long distance and live in, and alternated the two, they are not comparable in regards to the mental requirements. In short, when long distance you can always hang up/block/not make contact. That element of control stays with each of you if you unhappy with the situation. While this can happen in real life, it is a lot more difficult to avoid someone you share a bed with!

Essentially what I am getting at is the difference between a long distance, and "live in" (im avoiding r/l for the sake of avoiding confusion) vanilla relationships. While the people inside the relationship may build a strong bond through the long distance relationship, most would not consider it a proper relationship till it is taken to the point of meeting and being together in "real life". I feel that slavery falls under the same type of thing.

Regards,

Arch