I lived in the general area where Dee Dee and Gypsy lived. Even before the murders, I was vaguely aware of them because they were on the news every now and then. Dee Dee was a very good PR person.
After the murders, many people shared memories of seeing the two of them out and about and found that they were very pleasant and approachable. However, apparently Dee Dee had a habit of helpfully telling strangers how they could make a donation to help Gypsy.
In the series, when Dee Dee consulted the attorney about getting guardianship of Gypsy, I almost laughed. We had to go through that process with a genuinely disabled relative and not only was it expensive, but it involved extensive tests and examinations by more than one doctor. The disabled person was assigned an attorney by the court to ensure his legal rights were protected. (If he had been able, he could have hired the attorney of his choice.) This wasn't in Missouri, so it may be different there, but in this state there were safeguards at every step.
In our case, the guardianship was granted, but afterward, the guardian had to file a report with the court every month, accounting for every penny that was received or spent. There were other restrictions and requirements as well.
If Dee Dee had actually filed for guardianship, the fraud she was committing would likely have been discovered in the process of getting everything needed for court. If, somehow, some way, the case had slipped by all of the safeguards and Dee Dee got the guardianship, she would have discovered that she had just tied her own hands in her attempt to further imprison her daughter.