Comment 2 for bug 900309

There's a problem when the current terminal supports 256 colors, but there's no terminfo file for screen-256color.

To reproduce the case of a missing terminfo (e.g. old system etc), just set SCREEN_TERM="-T screen-256color-notfound" in the snippet above.
Screen will then fallback to using vt100 (at least the screen I was using when encountering this).