Service Books and BBM on WiFi

[justin908090]

Hey!

I'm thinking of getting a Blackberry 8520 but I can't really afford paying so much for data plans.

So I was researching and I found out about certain incidences wherein people are able to send BBM messages through WiFi without the sim.

So I was thinking... what if I borrow the sim of my friend to get the service books then return the sim, would I be able to send BBM messages? Also, I am assuming that these service books contain information specific to the BB of my friend so, hypothetically, if I were to edit the service books into like say my BB pin, would I get to share that unlimited data plan?

Sorry if I understood the terms incorrectly. Any input would be deeply appreciated.

Thanks!