buddy, that was meant to force them to burn stuff and get rid of anything they wanted: threatning to drop the kids from the tree through a broadcast.
Thats easier and extremely quickier than killing every single giant in the island and doing all the stuff by themselves.
That has nothing to do with Gaban approaching her and her being so concerned about coming close to him.
If stabbing the kids neck was such a must, she wouldn't have bodied the Strawhats, much less let Usopp burst her head her just for fun, she would've threatned to kill the kids. And guess what? That was a must once she saw Gaban, what a coicidence isn't it... yeah its a coincidence for sure.