[wp-testers] Question about SECRET_KEY et al.

[Xavier Borderie]

Quick questions (and hopefully quick answers :) ) about this subject:

Let's say a user has been using SECRET_KEY since v2.5, and has not
changed that when 2.6 came. So, he doesn't have AUTH_KEY,
SECURE_AUTH_KEY nor LOGGED_IN_KEY in his wp-config.php, but he does
have SECRET_KEY. Does WP fallback to SECRET_KEY when he can't find the
three other ones ?

If the user replaces SECRET_KEY with the three new keys, can he expect
some login failures?
If so, how can they be best avoided (apart from
log-off/delete-cookies/log-back-in)?

(yes, I read this
http://wordpress.org/support/topic/170987
and this
http://boren.nu/archives/2008/07/14/ssl-and-cookies-in-wordpress-26/
which answer these partly/indirectly, but I'd like direct answers)

Thanks a lot, guys !

-x.