1) The temp file is only for playtesting purposes. When exiting playtest mode, it already gets deleted. So usually you won't have it around when quitting the editor.
2) As long as you don't terminate the editor process, the editor will always ask whether you want to save the level or not. This even applies on any crashes (as long as Windows still reacts).
1, unless this is a new thing for the next update, is not true it seems. I just tried entering playtest mode, then exiting it. Temp level file remained. Only when I quit the editor, it disappeared. V1.8, maybe I'm out of date?
2, I was thinking more in the case of the accidental hit Esc, then clicking "No" (thinking "No, I don't want to exit"). With that being fixed, this is no longer an issue, I don't think. Although it could also be relevant to if the
entire OS crashes, or in case of power failure for those using desktops.