This should go without saying, but if anyone at your facility has ERRs in to places they could be selected for but would turn down, they're a gigantic piece of shit. It isn't as simple as 'oh he/she turned it down, it goes to the next person'. The entire NCEPT panel has already met, facility that fill all their available vacancies can't just take person X who should've been eligible. The only time I've heard of it 'working out' is if the next available person had an ERR into a place that didn't fill all of their vacancies. Not only does this potentially screw over potential co-workers, if you get selected for a facility that filled all their available vacancies, you're taking a spot away from someone who would've actually gone.
Don't blame your fellow controllers for how shitty the system is. They didn't put this in place. Lives change, sometimes HR forgets to remove ERRs from consideration even if you tell them to, people forget that their old ERR has actually only been in for 14 months, etc.
All of these problems are because of NATCA. NCEPT is the most anti-workforce thing they've ever done and they still won't admit their own incompetence. It makes any sort of career progression zero sum so that someone getting a promotion is directly correlated to someone else being denied one.
For the love of god just stop giving these morons your cash