Is it possible? Absolutely. But so what? Same thing could happen with hard line bidding or traditional PBS too. You just won't know it. Worst case scenario: Guy #1 changes his bid last minute and blows up #2. Guy #2 goes in and changes his bid to his plan B and blows up #3. And so on and so on. Could that happen? Sure. Now, how often does that happen? Rarely, if ever that I've seen, probably because I'm mid-level seniority for relief/reserve line bidding and also because most guys aren't jerks just to be jerks. They bid what they want and are done with it. Remember, there is NO bidding system in the world that is going to fix being junior. SmartPref does tell you how many bids senior to yours have been saved but that doesn't stop someone senior to you from changing their bid last minute, for whatever reason. But you know that if only 1% of bids senior to you have been saved, your confidence level should be low. But if 99% of bids senior to you have been saved and the bid closes in 20 mins, your confidence should be higher that what you see is what you're gonna get.

I'm not sure what you mean by "system not been implemented"... SmartPref IS a thing. It has been how relief lines and reserve lines have been built for over a year now. The story of how SmartPref came to be and how it was implemented is convoluted and shrouded in company/union politics and there are probably folks with more and better background than what I can tell you. Suffice it to say, it was basically snuck in on the junior pilots as way for the company to save money and for the union to protect the senior pilots. It ended up not mattering anyway, because now the company can't or won't build lines with more than 12 days off so the point, at least for now, is moot. Just my opinion.

Now as far as how it relates to the merger, again, probably folks out there that can tell you more than I can. But from my perspective, at the time of the merger, ASA had their system they like and XJT had line bidding for all pilots. ASA had their "vacation low" deal and XJT had their "trip touching". On the XJT side, the company and the union had been kicking around (but had not implemented) PBS for a long while as a way to cut crew costs and improve efficiency without making it an overt pay cut after signing the cost-neutral deal with United. All that was well before the merger was announced. Now SmartPref vs. Flightline is just another battle in the standard whizzing fight between unions trying to protect turf during a merger.