This could certainly be the case, and you put it well. But maybe... I can understand Cindy's point of view to be honest. Imagine if your daughter had never shown any sign of violence or maltreatment of her little girl, (forgetting all the morbid speculation that's been out there, the actual history is that there had never been any signs of neglect, never any injuries, etc. Caylee was a healthy, happy little toddler all the way up to June 15, 2008.) All the friends and family said Casey had always treated Caylee well and would never hurt her in any way, nor would she just let Caylee be missing. They were all completely baffled. According to all the friends, Caylee was very attached to Casey, too, loved being held by Casey, when visiting friends Caylee didn't like to see Casey go out of her sight, etc. She had a very good, positive attachment to Casey, and vice-versa.
Suddenly in May and June 2008, Casey is running with two new crowds, taking Caylee around these two apartments where Caylee is exposed to LOTS of new people, and Casey herself is exposed to lots of new people at Fusian etc. (And by their own admission there were drug users and even drug sellers among these people. There was also the weird guy who scratched one of the shot girls. Who knows who all was around.) Casey is very busy socializing with all these new friends and might not have been watching as closely as she should, might have been a little too trusting. She'd always had Caylee around her friends, didn't think this was any different. Coinciding with Casey moving in full time with new facebook acqaintance TL and his roommates, and all their hip-hop promotions crowd, something happens to Caylee and she's missing.
Casey doesn't report the disappearance and when finally confronted, is in some kind of la-la land, seems to have forgotten about Caylee. She didn't flee, she didn't hide, she didn't concoct a logical story to cover her own behind, she doesn't seem to understand the urgency of the situation at all. She is oblivious. She only wants to talk to Tony, she doesn't care about anything else. Her tone of voice and behavior/attitude is like a different person, according to old friends, she doesn't seem like the same person at all. They were shocked.
Some friends and family had seen Casey have something similar to seizures, when she was asleep, both before and after Caylee going missing. They also knew Casey had a history of not always making that much sense, they would take what she was saying with a grain of salt. She would sometimes just agree with what others were saying or tell harmless white lies. They knew she had occasionally stolen small amounts of money too, and now she had apparently stolen $600 from one of these new people.
If I were the family I would be thinking
(a) was there a bad egg somewhere among these new people Casey had had Caylee around, was there a pedophile or a violent person? Yes, pedophiles can be normal looking young men and women, too. Had Casey been so wrapped up in her new social life she wasn't watching closely and someone on the periphery had gotten Caylee?
(b) Did Casey not report the disappearance because she didn't want to rat out a friend or boyfriend (maybe even afraid to rat), or because she was traumatized in some way and in disbelief, or because she'd actually thought Caylee was with a friend, or because she didn't know what to do or how to face her parents?
(c) Had Casey had the onset more serious mental illness, like a schizophrenic or manic episode, or a medical brain issue of some kind, maybe delirium due to sleep deprivation, which caused her to lose time or fail to understand or report the disappearance?
(d) Had she been drugged by someone in this crowd, or started using more drugs than has been admitted, increasing her confused/delusional thinking and behavior, etc.
(e) had there been an accident she was afraid to admit or which had left her traumatized?
(f) Had she finally stolen from the wrong person, someone more dangerous? (i.e. TL's story he told Lee while wired for the police, about their drug dealer who had had money stolen and Casey talking about having money soon after that.)
I'm just saying if I were Cindy or any of the old friends, I could completely understand them thinking it could be someone else. That would be a perfectly logical suspicion that I would expect the family and old friends to have under the circumstances.
I'm still not sure what happened. I'm not sure how much Casey knows. She could have done it, of course. Maybe LE know stuff we just haven't seen yet. But as much as it could have been Casey it seems like it could just as easily have been almost anyone else around (from what we know so far). I can completely understand her mother thinking maybe it wasn't her.