Spyglass - 1:34 pm on Jan 7, 2011 (gmt 0)
the OP is talking about additional sitelinks that appear under your ad when in the banner position, not about description lines #1 and #2.
Our Google rep has categorically told us that using symbols in your sitelinks is not allowed, however they aren't out actively looking for them.
If however a competitor were to complain about you using symbols in your sitelinks, you would then face disapproval of those links. (This is UK based advice).