highly unlikely. if there was enough static to disrupt the mouse signal you would be at the least causing a buzzing in your speakers or possibly a small electric shock. keep in mind that your body will ground the mouse when you touch it which makes this even more unlikely.
now what can cause the mouse to jump around is the surface you use the mouse on. highly contrasted surfaces such as small white text on a black background, reflective surfaces or uneven surfaces can cause tracking issues. the mouse cursor will appear to jump around on screen. this could possibly make selecting files harder.
perhaps she just does not know how to delete files properly? this was my first thought.