When have you EVER received any e-mail that didn't have you in the To
or Cc headers other than newsletters to which you subscribe or other
opt-in mailings which obviously you should be whitelisting to avoid
them tagged as spam?  You should already be whitelisting all your
known senders (i.e., anyone listed in any contact-type folder) and any
other repeated wanted mailings.

So, let's see, you allow any sender using the Bcc to hide your e-mail
address (and other e-mail addresses for an unknown number of
recipients) from whom you never before have received e-mails and from
who you have yet to whitelist?  Yes, on the first occurrence for a
subscribed newsletter, confirmation e-mails for registering at a site,
subscribing to a mailing list, online orders then you might not be
listed in the To or Cc headers but then you are expecting an e-mail
from that source that you opted in to receiving their mailings and it
should show up soon after subscribing and why I don't recommend
immediately deleting upon delivery but instead shoving into the Junk
folder and purging items over N days old.  You then have the means to
check for the expected e-mails and whitelist them for their future
mailings.

You like to leave your Inbox open to anyone that chooses to use the
Bcc header.  I don't.  I doubt that I'm alone in this tactic.  Most
wizards or even long-time e-mail users will recommend filtering *in*
what you want to keep to avoid or reduce spam.  I first blacklist
(block), then I whitelist (filter in), and then I detect spam (filter
out anything not explicitly filtered in).  My "Me no in To/Cc" rule is
part of the filter out rules but this particular rule allows for
recovery of one-time mails that I want to keep and may choose to
whitelist (if those wanted mails will repeat).  I also use SpamPal
which can automatically whitelist e-mail addresses after receiving
non-spam mail on N separate days (I chose 15 days), but I haven't
bothered using that option yet to filter in those e-mails.  I figure
if I want those repeat e-mails that I don't need SpamPal to figure
that out and will simply add the sender to a contact-type folder
(included in a whitelist rule of known senders) or add the sender to a
whitelist rule.