Frankly, occupancy "rules" asside, the real issue where studios concerned is the type and quality of the bedding. Most DVC studios (with the exception of OKW) have a queen sized real bed and a pull out full size sofa. Very few people other than children are used to sleeping on a full sized bed of any kind, and a sofa sleeper, while technically the same as a double sized bed is more difficult because of the quality of the mattress. I can see 3 adults in one of those where there is a full sized pull out, and even 4 adults who can sleep in pairs at OKW, but beyond that, I don't consider the studios to be appropriate for most groups that have more than 3 adults or 3 children if one is under age 2.
Personally whatever the group using the studio can deal with is fine with me. It's none of my business