If there's a message for IE, I'd assume there is also one for every other major browser running an older version past a certain specified point. So yeah, there probably is.
I don't know about Safari, but Chrome, Firefox and Opera either auto update, or inform you about an update when they open. So a message like that would likely never be seen. (Chrome updates in the background, so you never even know you have up update unless you relaunch and something new is apparent. It also doesn't give you the option of turning it off.) It's far less likely for someone to be running an older version of the free browsers.
It can be added that the phrase you_are_using_out_of_date_browser_upgrade redirects to chrome page. If someone prefers to advice another browser, just edit this phrase.