I see nothing wrong with the seatlock... and it's certainly not throwing them under the bus. They just got hired with a carrier with a HUGE amount of retirements coming.
Refer to the above post, commenting on Slow's idea. Why are we simply "shooting ourselves in the foot" with obstacles (seat locks) for new-hires, based solely on the fact that, "THIS IS DELTA AIR LINES, & THEY SHOULD JUST BE THANKFUL FOR AN INTERVIEW & AN OPPORTUNITY TO WORK WITH OUR HOLINESS."
If the company wants something, (i.e. seat lock for training costs) make them "PAY UP"!! Like Sinca's avatar, FUPM!! (Originally coined by the Continental guys, I know.) Again, I haven't seen what LOA 31 consists of, but each & every time the company wants something, they toss us a "carrot" and we sacrifice a "horse" for it.
I would have been perfectly happy with or without a seatlock on my initial NYC 88 award.
Good for you. Don't speak for the rest of the new-hires.
I thought it was horribly inefficient that I could bid out of a plane they spent thousands of dollars training me on... and I only got 115 hours in it.
Remember that quote when applying for a management position, you'll fit right in. 
It's not our job to correct (pay for) the inefficiencies of management.