is mutex lock on mongrel needed for activerecord?

I've seen a bunch of posts in various place about whether or not
mongrel needs to lock when doing activerecord queries. I'm talking
outside the context of rails here, for example, in a custom mongrel
handler. It seems to work fine for me without a lock, but I haven't
done any extensive testing.

When I ask around, some people say you need that mutex lock with
activerecord. Some say you don't because the need with rails is
really from actionpack. But, most people seem to say something along
the lines of "in theory you shouldn't need a lock, but I'd just use
one".

I was just wondering if anyone has any insight to whether or not a
lock is needed when using activerecord in something outside of rails/
actionpack such as a small mongrel handler.

Thanks for any advice!