The comment above mine is correct, although I'm not sure the definition of "scab" is someone who wants to go into management. The first qualification for management is (should be) that you want to go into management. Telling your management that you want to be considered is the first step. It's not offered by seniority.
Selectivity will be determined by how badly the management ranks are understaffed. If it's staffed up in a rural area and people have to retire to make room, they're super selective. If it's a night hub or a preload in a metropolitan area, you might just have to fog a mirror and have a background check that comes up "not too bad".