Actually, I've just realized that if you ask for
EntityVersion.Proposed, when it hasn't been defined by starting an edit, you'll get
EntityVersion.Default (which in that case will be
EntityVersion.Current). Checking this clearly won't work, you'll have to implement what you suggested.
Sorry for the wrong information. It made sense, but it didn't seem to be working correctly when I tried it out, and when I checked teh documentation, I saw that I'd forgotten how EntityVersion handles undefined versions.
Yours,
Robert