Blueydoo: last time i used to laugh at my colleagues when they get stressed abt P1. Then my turn lor!
If you join alumni, u must joined at least 12 months before the registration. And you will register your kid in Phase 2A1. But if you didn't join the alumni, you will register your kid in Phase 2A2. Alumni is almost 100% guaranteed you can go in. I've never heard of any schools where u joined alumni yet still have to ballot.
Depending on which school you are registering. There are some schools where even old girl/boy (without alumni), you might need to go thro' balloting. I think historically, Catholic High, Rosyth, Ai Tong, ACS pri have been thro' that before.
So its better to call the school and asked. I called my school last year to enquire if there is a need for me to join alumni. The teacher in charge of P1 registration told me no need to join. So i didn't. But his advise is based on past historical data. It so happened this year, this school had so many applicants in Phase 1 that by the time its my turn to register, left with 100 vacancies.
anyway, its always free of charge to call and ask... no harm asking the school. U can email them too. The person in charge should reply u.