It's certainly possible. I don't trust a word that woman says.
I also found her little interaction with Ben most interesting. He definetly knows who she is..what I find confusing is the fact that he seems unwilling to out her to the Losties.
Yet he was so willing to out Naomi..
I would
n't say this harms your suggestion, but it certainly complicates matters.
Ultimately I would agree that it's highly possible that these are her people who have just landed on the island. Obviously they have advanced further since she arrived 16 years ago (these people seem VERY advanced and specialised - although I suppose Danielle is aswell, for her time).
Another possibility is that this is a rival group to her people - perhaps she was Dharma and these are another group..perhaps an anti Dharma faction, a resentful Hanso alliance, or a completely different group.
I like your idea about Danielle killing her people because she changed her mind about the island and wanted to protect it..this could well explain why Ben is so unwilling to out her..this could indicate that he sympathises with her for this reason - same goals, different ends, kinda thing.
However, one thing which complicates this even FURTHER, is her SOS transmission - if she didn't want to be found, why did she record it in the first place..and then leave it running for 16 years? I thin this was briefly explained by the 'Looking Glass' jamming system, but still..why take the chance..why not destroy the radio tower if you so don't want to go back...
ALSO, just had a thought..what if the REAL reason for Rousseau not wanting to go back is because she knows what happens to people who leave the island..Lenny (okay, he wasn't on the island..but still), Sam Toomey (see Lenny), Hurley, Jack...