Yes, but with record profits and the union playing nice at mainline, management would be foolish to rock the boat. However, the next economic downturn at the majors is going to be way worse than the previous ones. The best advice is to always have a back up plan even if you get hired by a mainline.

Pinnacle is a worst case scenario, they got all of the Colgan pilots, but none of the Colgan airplanes. This could easily happen at a mainline if the union isn't careful. A separate union like SWAPA can craftily side step around it carefully, whereas ALPA has no choice due to ALPA merger policy.