Caster or device for floor tracking, but non-supportive

[FRC1771]

<R06> ROBOTs must use ROVER WHEELS....No other forms of traction devices (wheels, tracks, legs, or other devices intended to provide traction)are permitted....The intent of this rule is that the ROVER WHEELS be used in as close to their “out of the box” condition as possible, to provide the intended low-friction dynamic performance during the game.

With this rule in mind, would it be legal to install a wheel encoder (non KOP wheel)in a caster arrangement to measure velocity and position? This wheel would not provide traction as the only resistance to turning would be encoder friction. The KOP encoders won't do much good for velocity and position detection because the wheels slip too much.

If the preceding is not legal, what about an optical device (like an optical mouse) in contact with the floor, riding on a teflon bearing?

[GDC]

An information gathering device like this would not be considered a traction providing device, and would thus be permitted.