I have had the reflector thing happen before, too.

Anything that you jam on or between the spokes can change the spoke tension and thus affect the trueness of the wheel.

If you add reflectors, make sure that they touch or attach to only one spoke or you may see these kinds of wobblies again.

Unless you ride on the street or at night, I would lose them. Heck, even if you do, they don't really guarentee that people willl see you so you might want to ad some reflective tape to your jacket and lose them

- Jeff