A company may use another's AOC under certain conditions - it does not by default makes the AOC company responsible for everything - the "piggyback" company still has a responsible person aircraft, etc, at least that is how I understand it.
It has been quite a few years since I was involved with Solenta, but I still believe they are some of the best outfits around and do not think they deserve some of the comments, even though it's a rumor network!
