Do the parents do anything else at home other than the crib when she is throwing a tantrum? I would ask exactly what they do and than do the exact same. (If your not already doing this) She is still young so maybe she needs a bit longer to learn that every time she misbehaves mom/dad and dcp are going to put her in the crib.

Also, you said she now points to go to her crib....are there any constant variables to her tantrums? Is it when a particular child is near her or if it's too loud or near snack/lunch time etc?