[spoiler]That's exactly what I was going to do!
Since I have higher initiative, I'll say Dick hears Greed coming and delays, then moves to flank with him and also tries to disarm the girl of the necklace.[/spoiler]
"That's not a very nice way to treat your Mom, kid."Dick drops the vial of acid, and winces as it breaks and splashes on him, and then moves to flank the girl with Greed. He also decides that the necklace might be what's behind this, and besides it's the items they're really after, anyway. They'll probably pay more for it than the little girl...
He vanishes from sight, and then tries to grab it.
[spoiler]Swift action to activate Cloak of Deception. So that's a +4 in total to attack from being invisible and flanking. The girl is denied her Dex to AC also, presumably. Dick is an unarmed swordsage, and so is considered armed even when making unarmed attacks, if it matters (he's invisible, so she shouldn't get an AoO anyway, unless she can see him somehow.)
Also, can we assume that he goes around with Island of Blades active all the time? Or does he have to activate it when combat starts? It might change where he has to move to to flank.
Attack (disarm):
1d20+6=24The +2 from flanking and +2 from being invisible are
not included above, nor is the -4 from using a light weapon (unarmed strike).
If Greed has already swiped the amulet, Dick will try to knock the girl out by punching her with subdual damage. I guess we can keep the attack roll, since it's the same.
Damage (if needed):
2d6+7=9[/spoiler]