Whether they are released is up to the mediator. Only time will tell there.

However, the "last hour settlement" to which you refer is a misnomer. IBT can't "settle" anything. There may be a last hour TA, upon which the RAH pilots will vote to decline or ratify, but IBT will have no say in the vote. Having been in this position before, as you say, I am surprised you would not know this.

Even if the expected last hour TA is substandard or inadequate, to include signing bonus/retro pay, it's terms will be based on what BB & co were willing to concede just as much as what IBT was willing to demand, and vice versa. The strategy involved goes layers deep. A poor TA presented to the pilots as the best offer the company is willing to provide can easily become a rallying cry.

At the end of the game, whether the RAH pilots vote to ratify a substandard TA or stand firm is on the pilot group. IBT won't, because they can't, settle anything.