有D奇怪？今日收到教育處的信要我確認參加大抽獎

AhWing

I've got a similar letter too today.  Really surprised!  
From my understanding, we cannot join the Lottery system only if we've got an offer from DSS, but not from a private primary school.  So, does the Government have the authority to force us to reply this letter?  Btw, the letter did not mention the consequence if we don't reply it.  So, I wonder what if I just ignore the letter and don't reply it?!
Any ideas?