I think in order to answer the second question you'd have to suspend disbelief for a second. Any student or mass with such charge would have a huge potential difference relative to Earth, so I would not be surprised if it very quickly discharged (because the electrons in earth would "want" to flow back to the student) and returned to neutral. Which among other things is why we get lightning.
I know that sounds a bit pedantic but then, on the other hand, you'd probably have found that we should have left the Sun's orbit a long time ago if there was such a concentrated charge allowed to attract the Earth to it over a long period of time. Such as a cloud.
So, suspending disbelief:
The gravitational force on the Earth due the the Sun is approximately 3*1022 Newtons. So, basically, because in fact this is tiny in comparison the to electrical forces due the the students, it would likely take only one student to escape from Earth's gravity, and the reactive force would be many times large enough.
Probably.
