I put together a simple seat lock mechanism to hold the seat down and keep curious hands out of my underseat storage area...
It's almost too simple... voilà!



One nice thing about the location is that it doesn't interfere with the seat latch that comes OEM with the Ruckus.

A simple loop of steel cable fastened by two terminal crimps provide a quick and easy way of securing the seat to the built-in helmet lock.

It took me some time to determine the best location for such a beast.
The length of the cable is critical for the mechanism to work properly, so I recomend making a few different lengths and try each one for fit.
Fasten the assembly via the inside of the user manual compartment using a good size pop-rivet WITH a backing washer for support; fastening from the inside will seat the rivet flush to the wall, that way your scooter manual will fit back into place.
Works like a charm!