With a B-1 / B-2 renewed tourist Visa, if you leave the couuntry for
Canada/Mexico/or contiguous U.S. territories and come back to the U.S.
within 30 days (and the renewed Visa expires in that time), does your
Visa get renewed under the DOS's Automatic Revalidation clause
assuming you have a valid arrival / departure record (Form I-94) with
an un-expired period of admission?  If so, for how long is the Visa
revalidated?  Are there any other issues involved other than not
applying for a visa while away?  I sincerely appreciate any and all
answers.  Please have conceptual knowledge of this area of the law
before answering because I may ask for clarification if the answer
does not reflect an accurate understanding of the provisions involved.
 Thank you all who answer this question.

-joe

I'm not an expert but I was an F-1 student in the US, so this is what
I know..

A Visa is a permission to enter a country, not permission to stay.
Your arrival card (I think it was I-94) is the permission to stay.

You can enter anytime to the US, as long as your Visa is valid.
You can stay as long as what your I-94 said.

So, if your Visa is expired, you will not be able to get in to the US.

Before the 9-11 thing, it is possible to get an exception if you exit
to and enter from Canada/Mexico. However, the latest news I got is
that the border became more strict, where it very likely to deny your
expired visa upon re-entry. Also, it was possible to revalidate your
visa in neighboring country (Canada/Mexico), but now it is limited
only to Canada/Mexico resident only.

These are from my F-1 Visa experience, and I know that B-1/Tourist
Visa is a lot more strict than F-1.

I know that while permanent resident applications are pending, one
must get a separate travel document that will allow them to exit and
reenter the US without their application being cancelled. Some
countries I've lived in also required this "re-entry permit" if I
wanted to take a trip and then return under my original visa: if I
didn't get the permit first, my visa would be cancelled by immigration
when I left the country. I'd call the immigration department or your
countries embassy in the states and ask them. Get names (or numbers if
they only give out employee numbers) of all people who told you
something in case they were mistaken. Or better yet, get them to fax
you the rules! Hope it works out well for you!

oops. i misread the question a bit. It is my understanding  that if
you leave under a tourist visa, it is cancelled when you leave. when
you come back, you get a new one: unless there is some reason they
don't want to let you in - be sure to have either proof of having a
lot of money or a valid plane ticket leaving the U.S. in the future.
If you are a citizen of a country that actually needs valid visas to
come to the USA even as a tourist, you'll need to get one prior to
arriving though.

Non USA content just for fun: When I lived in Japan, many of us would
leave and come back on 90 day tourist visas, only to repeat again in 3
months. Some people did this for over 5 years, ha! But once I bought a
round trip from Tokyo to Seoul, stayed three days, and since I didn't
have a ticket with me to show that I planned to leave Japan once I
arrived there, Japan Air Lines wouldn't let me on the plane back to
Tokyo! They were trying to make me buy a ticket at the counter which
is of course a very expensive way to buy a plane ticket! So I missed
the flight and luckily they stamped my ticket and I went to the
NorthWest (I think) counter and they put me on their next flight to
Tokyo for free. JAL must have some agreement with the Japanese
government to not bring people in who don't have proper documents. But
NorthWest couldn't care less. Of course I had absolutely no trouble
when I arrived in Japan anyway.

ah...gotta love world travel and foreign living

Just an out of topic comment, isn't this expire date a bit too long
for a 'time sensitive question (6 days)' ? :)