If it was a performance issue with the 170 or 190 it's not the first time they made that kind of mistake.

About 7 or 8 years ago CHQ management assured Delta that the EMB135 could get in and out of EYW and fly to MCO without any issues. They found out only a day or two before that it might not. After last minute scrambling and talking to Embraer they found out that the 135 could indeed do it with 37 people and full bags but only with a few hundred lbs above min fuel with no alternate. If any more fuel was added they would bump passengers. So they got away with it. However, on several occasions due to MCO needing an alternate they needed to fuel stop from EYW to MCO in RSW! Not one of Chautauqua management's (now Republic), finest moments.

In light of this I wouldn't be surprised that someone in management screwed up badly. But what do I know?