I wouldn't say there is a downside,

Then let's try it.

but who knows if that solves the
problem for all readers, or that some other reader anomalies won't create
the same kind of "problem" with other subject line content?

Nobody, until we try it. Colon cleansing for prepends!

Jose
--
There are two kinds of people in the world. Those that just want to
know what button to push, and those that want to know what happens when
they push the button.
for Email, make the obvious change in the address.