I can't see that happening, for one good reason.
The vigilante justice would be swift, and wide spread to include not only Casey, but her parents and anyone that has sided with her.
And, just from judging from the protesters that stood guard outside of the Anthony home when Casey was home under house arrest, it would not take long for a lynch mob to congregate outside Hopespring Drive and wait for them to come out weilding their hammers and garden hoses.
Which, in the end, would only end up costing the tax payers of Orange County and the state of Florida even more money in going after those that would be charged with those crimes.