In statement Sony gave, they noted that “We have some tech demos that allowed users to play while standing up, however all the PS VR titles we plan to release in the future will recommend that users remain seated. We will announce further details of guidelines or regulations when ready”. Givent he nature of the control Sony has over the PS4, we can expect most developers will have to follow the regulations Sony will set. The few that won’t will be likely targeting the users that got PS VR for their PC.
The reason that PS VR is going to focus on seated play is because the PlayStation Move camera simply can’t track a large enough area. Tracking will likely be limited to a short-range for the head, arms and upper body. This leaves the HTC Vive, with its superior tracking cameras, as the sole provider of large room scale VR. For me, room scale VR seems to be the most exciting part so it will be interesting to see if developers will focus on that or go the easier route with Sony and Oculus.