Yes, Jeff I agree that there could be several reasons for Lureen's monotone relating the story of Jack's death to Ennis - she's in shock, she's likely recited it verbatim many times before, etc... Maybe that's the central question here - are we really so quick to jump to the conclusion where Jack is a victim of a hate crime, realizing Ennis' worst fears? Or is there a more 'innocent' explanation? I'm too jaded to believe the dressed up version (and shit, when does even the accident version become so much more palatable?!).
Another piece of the puzzle, though, may come to us thru Lureen - the hitch in her voice and the coldness - when Ennis relates that he and Jack herded sheep up on Brokeback in 1963. It seems that when she assembles those facts with what she really knows, fully realizing the connection Ennis had with Jack, perhaps that's when she herself realizes she's relating a glossed-over story of the actual event? At any rate, when she regroups, tells Ennis to see Jack's folks and about his wishes regarding Brokeback, she redeems herself admirably.
But as to the interpretation of Jack's death being a test - I'd never called myself bisexual before BBM - didn't see the point of a label. BBM and specifically BetterMost made it impossible to not acknowledge that part of myself. One data point doesn't make a trend, but it works in my case.