In fact, subs are often taking a bigger risk. They may be playing with someone they only meet for occasional scenes, who they don't know well and who has only a casual commitment to their welfare.
First off, if you are being intimate with someone that you don't know very well, you are taking unneccesary risks that (I believe) you shouldn't be taking, to begin with. If you don't know a D/s or a M/s well enough to know if they are in control enough to do their very best to avoid most risks then really I am not sure they should be putting yourself in that situation.

In saying that, you actually made my point about commitment. The commitment between D/s and M/s is much different (if not for that very reason... there are several others).

Though, you misunderstood me if you believe that I was simply speaking of a slave trusting a Master with her life exclusively during the sexually intimate experience. Sex IS a part of the M/s relationship but it IS NOT the entire relationship for many and extreme sex is not actually a part of most M/s relationships (it does happen to be a part of mine, though, I have spoke to many that are not into nearly the extreme sex that Master and I are). The trust I was speaking of when I spoke of a slave trusting a Master with their life was in reference to ALL of the choices a slave trusts their Master/Mistress with in their life/experience together. It is, for many, a life altering experience. I was refering to the entire experience and a M/s's commitment to it and the trust it embraces.