A play scene without sex does require that you trust the person to stay within the negotiated terms, just as when you negotiate a full on Master slave relationship, or anything in between. The level of trust required varies, not that you trust or don't trust. e.g. If I see a bottom, or a submissive (bottoming being that a person allows me to do things to and with their body having their input during the scene for changes and such, submitting being that I can do things with their mind inside the negotiated terms without them trying to direct or control things) that I would like to have a scene with. I can negotiate a scene that is simply a bare bottom spanking them on a kneeling bench. That only requires that they trust I won't harm them unintentionally by hitting their tail bone or any other careless act. It isn't sex, and it requires a minimum amount of trust.
As far as who enjoys play scenes with or without sex... Well I've known many submissives to enjoy a play scene without sex, I've also know submissives that look at play without sex as having cake, but not being able to eat the frosting on top. I've not noticed a percentage really, as most submissives I know tend to prefer to be in a sexual relationship with their dominant. Not all mind you, but most.