[PHP] php_admin_value's from httpd.conf Override'd in .htaccess files

[Juan Velasquez]

so, if I set php_admin_value open_basedir in httpd.conf,  and I give
.htaccess AllowOverride permissions,  can users Override the
open-basedir I set?   And, how can I give out some Override's, but not
php_admin_value's?