This comment seems to have slipped under the radar, but it answers the question about staff operating seat belts. So thanks @mba2012 for getting it right.
If the seat belt is fastened and the strap tightened, it interferes with the push/pull procedure, where the 'pull' is just testing the tension of the seat belt, not the primary restraint. If there is a hydraulic/ratchet restraint failure in such a scenario it wouldn't be detected, and the seat belt would be the only restraint with no redundancy.
The safety standards and codes that govern Amusement rides aren't just for parks. They're also for traveling rides that experience wear/tear/damage in setup/pack down and transport. It's one set of rules for every operator and every ride.
So while it's highly unlikely a ride like Rivals or ST would need a seat belt, people can and have been ejected from traveling rides, and severely injured or killed. Even a ride as mild as TRRR was able to fail in a deadly way, GL also failed in a way that could have been deadly - different rides, different parks, different reasons for failure.
Every safety standard is written is someone else's blood. Unlikely things happen. Operations are never slower because of safety, they are the correct speed to safely operate the ride.
At Village parks, operations are slower because of corporate culture, under-staffing and, in some cases, poor station design.
Removing the current locker system at SE won't speed up operations. It will just move all of the pocket checks to the front of the queue. SE pulls strong forces where riders are seated with their knees above their hips, which means anything in your pockets will fall out - potentially onto people in the paths below. So while you could have a better loose article system at the station, guests cannot be trusted to actually empty their pockets or understand the potential consequences of not doing so. For that reason, the park is not likely to change the current station or procedures.