Scoops does raise good questions but where I disagree with scoops is that he bundles everything into the the tandem theory and shows how they don't align with each other, thus making the theory unbelievable. Maybe there was no elaborate plan, no 11 year scheme, but they may have actually been with maura in those final days, and knew what she was doing, but not actively participating in a ruse. And if they did have knowledge if what was happening, I think a good way to deflect scrutiny is to say they didn't know her well (after her disappearance). Show me proof from before the disappearance that they didn't know each other well. That would hold more weight for me. After the initial scrutiny of Sara and Kate, they have basically been left alone for the ensuing 10 years, so in my mind, that makes a small secret even easier to keep. The heats been off for a long time, easy to say "I don't recall, I can't remember". It gets easier as the years pass. So while I'm not totally sold on any theory, I still have seen nothing posted by scoops or anyone else to disprove the tandem one. Scoops makes convincing conclusions but only if the interpretation of the actions and statements of others he offers are the only interpretations to come away with, and they are not.
I can also think of a big reason she may have needed to go away and it would be big enough for even a casual friend to keep the secret. Long term and systematic abuse. Whether it be verbal, mental, sexual or any other kind. Family can be biggest enabler of abuse within the family. Loving and caring as they appear, they could also be part of the problem. Often times an abuser does not appear as abusive to the rest of the world, so it could be anyone, but it's definitely a reason to disappear and to get help in doing it.
I can also think of a big reason she may have needed to go away and it would be big enough for even a casual friend to keep the secret. Long term and systematic abuse. Whether it be verbal, mental, sexual or any other kind. Family can be biggest enabler of abuse within the family. Loving and caring as they appear, they could also be part of the problem. Often times an abuser does not appear as abusive to the rest of the world, so it could be anyone, but it's definitely a reason to disappear and to get help in doing it.