I think it would be hypocritical of both a federalist party and of a sovereigntist politician if the sovereigntist politician chose to join and were accepted by a federalist party. I put my opinion on policy here.
Joining the NDP would be a betrayal of a principle that she (I assume) feels is important, that being striving for Quebec sovereignty.
and @ Stockholm too
Aside from the fact that this is completely speculative, and irrelevant to this thread (as mentioned above)
And it is false. Unless personal support for sovereignty is some special sort of heresy, unlike every other issue on which party members hold opinions that might be different than official policy without signing a blood oath - in which case one wonders how it hasn't come up before with other Quebec members who are also likely sovereigntist. (that's a bit speculative)
But I have no doubt this is the first and only point that would be glommed on by many in the anglo media, completely ignoring the real issue, and the real significance of her leaving caucus.
My point above about it being win-win for the PQ so long as people react in a certain way? THis is a good example.