It looks like you may have discovered a problem with the silent flag
as designed. The use you present is exactly what the silent flag was
designed to address; but it appears that it doesn't actually hit that
use case.
I've just opened #15570 to track this problem, and since this is a new
feature (which will require a backwards incompatible change to fix),
it is a blocker for 1.3 final. The fix will be to make silent *always*
put the value into context, but not render a value. This is the usage
that your second sample suggests as appropriate usage.
Yours,
Russ Magee %-)
... and, FYI: Fixed in r15773.
Yours,
Russ Magee %-)