Gnus doesn't quite hide an entire emphasized signature

[Karl Kleinpaste <karl@justresearch.com>]

I hide signatures in some mailing list groups.  Because mailing list
host sites are forever adding yet more crud to their trailers, my
gnus-signature-separators has gained elements like this:

"^____________________________________________________________________________\nto unsub"

Here's a sample blob of visual noise at the end of all messages on one list:

| ____________________________________________________________________________
| To unsubscribe from Y2KPrep, please send a message with "unsubscribe" in the
| body (not subject) to mailto:y2kprep-request@list-server.net. To unsubscribe
| from the *digest* version of Y2KPrep, send an "unsubscribe" message to
| mailto:y2kprep-digest-request@list-server.net. For other mailing list
| commands, send a message with "help" in it to either address.

Note the presence of "*digest*" in this trailer.  When Gnus displays
messages from this mailing list, the line of underscores is left
present, as expected (and in boldface)...but the word "digest" still
appears as well, all by itself, in boldface:

| ____________________________________________________________________________
| *digest*

It appears that emphasization in signatures defeats signature hiding.
Weird.  Screenshot at http://www.cs.cmu.edu/~karl/pgnus/hidesig.gif.