Yeah, I know about the ban on NCAA play - I was talking more about the period between 1995 and 2001 (I think, sometime in the early 2000s anyway) when the NESCAC opened itself up to NCAA play but simply awarded its conference bid to the regular-season champ due to the "one postseason tournament only" policy you referenced. I guess I would compare it to a macro version of Plattsburgh's 6 straight conference titles from '97 to '02. Plattsburgh only actually ran the SUNYAC tournament without a blemish in two of those seasons, but the minigame/best of three format used at the time allowed them to assert their dominance by taking away the possibility of a single-game upset. The mid-90s NESCAC was like a season-long tournament (sorry to have to use the college football cliche), amplifiying the same effect that Plattsburgh used to its advantage into a situation where an upset champion was impossible by definition.
If the NESCAC used its current tournament format from the get-go, for example, Middlebury would've had to play 15 extra games over their run, and a loss in any of those would've put a NESCAC team besides Middlebury in the tournament. I'm not saying that things would've played out differently (it's more than tempting to throw out the law of averages when it comes to Middlebury, and they certainly could've accomplished the same feat by taking the at-large route to the national title - in fact, that's exactly what they did in '99), but the conference would've had an opportunity for participation on par with other autobid recipients, in any case.