Per intestate succession under Florida inheritance law, Caylee's next of kin are equally 1) Caylee's mother Casey and 2) Caylee's father or Caylee's paternal grandparents if Caylee's father is dead. Florida Statute Section 732.103(2) and (4)(a)
http://www.floridaprobatetrustlaw.com/2009/12/articles/probate/florida-inheritance-laws-no-will/
George and Cindy can only claim rights as Caylee's legal next of kin if Casey murdered Caylee and Casey's next of kin status passes to them as if Casey had predeceased Caylee per Florida Statute Section 732.802(1)
http://law.justia.com/codes/florida/2010/TitleXLII/chapter732/732_802.html
"732.802
Killer not entitled to receive property or other benefits by reason of victims death.
(1) A surviving person who unlawfully and intentionally kills or participates in procuring the death of the decedent is not entitled to any benefits under the will or under the Florida Probate Code, and the estate of the decedent passes as if the killer had predeceased the decedent. Property appointed by the will of the decedent to or for the benefit of the killer passes as if the killer had predeceased the decedent.
...
(5) A final judgment of conviction of murder in any degree is conclusive for purposes of this section. In the absence of a conviction of murder in any degree, the court may determine by the greater weight of the evidence whether the killing was unlawful and intentional for purposes of this section."
To enforce their next-of-kin rights at Casey's criminal trial prior to Casey being convicted of murdering Caylee, the Anthonys would have to obtain a court determination "by the greater weight of the evidence" that Casey's killing of Caylee was "unlawful and intentional." It would be pretty astonishing for the Anthonys to do this if their purpose in attending Casey's criminal trial is to show their support for Casey's innocence. OTOH these are very unpredictable people. Who knows what they might do?
Katprint
Always only my own opinions
Edited to add: I think the trial will be MUCH more entertaining whenever the Anthonys are there. It would be interesting to see how George, Cindy and Lee react during testimony accusing George of abusing Casey, Lee molesting Casey and Cindy blaming Casey when Casey goes to her for help. I would not be surprised to see more hand-raising, making faces and shouting back at witnesses on the stand, too. Hopefully George won't be able to smuggle a baseball bat through security nor will Cindy be allowed to bring her hammer.