from:
http://www.transitlink.com.sg/ezlink_ns.html
USAGE
When alighting from buses, NSF who have bought a BCP/HCP should
still tap the concession card against the entry and exit card
readers when boarding and alighting from buses. Although no
deductions will be made, it will ensure that a transfer rebate is
given for valid transfers when the electronic concession pass is
not in use.
it sounds to me transfer rebate is still given leh? especially
the last sentence.
The rationale given is that, they encourage to tap out at all
times instead of only when you're transferring from a paid ride to
a paid ride (read "when the electronic concession pass is not in
use"), just in case you miss out on your transfer rebate if that
transfer happens to be valid.