Tim's launching a Traveller campaign, and we got together last week for a character generation session. Tim opted to use the Ironman variant, where if you fail a survival roll during a background term, you die. No ifs, ands, buts, injuries, being cryofrozen for a couple years, being kicked out of the career, or any of that nonsense. Toast.
Tim's reasoning for this decision was that it would let him remove term caps by balancing the potential for high skills and lots of starting perks with the increasing risk of death. Without Ironman, our experience is that most people will go straight for whatever term limit you impose, but here there was definitely much deliberation about whether or not to continue.
From the player's perspective, though, I was a fan of it for another reason - it lets you dispose of really terrible sets of ability scores. Rolled a set with two 2s and nothing over a 7? Join the Marines, see the universe, get yourself killed during boot camp. Oops. Guess you better roll another (better) set. Nobody in our group ended up playing the first set they rolled, and Drew went though I think four or five casualties before finally getting a survivor. The ability score distribution of the characters who did make it are uniformly above average, with only a pair of -1 stats between the four of us. I think this will help with one of the issues we observed previously in Mongoose Traveller, namely the wide disparity in capability between characters, which I believe wide disparities in ability scores contributed to significantly.
I guess the modern equivalent mechanic would be DCC's character funnel? Haven't played DCC, but it sounds like it serves a similar purpose, of weeding out terrible sets but putting the good sets at (fairly significant) risk too.