Questions about the bond/capital note !

Would someone please explain how the system is operated, I am really confused by the bond/capital note issued by some international schools:

1. Is it a prerequisite to have the bond/capital note before I can apply (or study in) a particular school
2. Is the bond/capital note grant my child the full rights to study in the school, no matter whether he's stubid or bright?
3. Say I passed the admission interview or test or whatever, then I need to find someone holding the bond/capital note and negotiate a price with him?
4. What if I can't pay the price the holder(s) asking?
5. If I am the holder, can I keep the bond/capital notes even after my child leave the school and wait until the price is OK for me?

Thanks a lot!