Wow, thanks for the replies

What is WBI?

I am on the QF31 from SIN - LHR, arrives at T3

then 2 hrs+ later I have to take BA 392 to Brussels from T5.

do I get all the boarding passes in Changi? or do I have to check in and out my luggage and lug it from one terminal to another?

Anyone knows why we have to show our laptops to customs? the purpose of it?

Or is it one of those, just follow and dont ask too much questions thing?