Since this was a source of confusion for me in the past, I like to make it visually obvious when I’m inside an ssh session in gnome-terminal, vs. on the local machine. This is the best solution I have found so far:

ssh-done() {
        setterm -term linux -inversescreen off;
}
ssh() {
        setterm -term linux -inversescreen on;
        /usr/bin/env ssh $*;
        ssh-done;
}

The reason why ssh-done is exposed as a separate function is that when ending ssh through Ctrl+C (for example, while at the password prompt), this gives you the ability to manually reset the terminal to normal again.

setterm in theory would also allow you to manually select a foreground and background color, though this didn’t work to well for me; in particular, it broke in various cases when commands tried to colorize their own output.

Totally awesome would be the ability to script gnome-terminal to switch the profile, but this doesn’t seem to exist yet.