I've got a new idea.

[colette]

I think I have got a new idea about Great Unknown and Fiona's mother. I think that Captain Widdershins didn't tell to Fiona when he told about the matinee accident. And maybe his wife died in Great Unknown?
Reasons to think so:
1. We know that Mrs Widdershins didn't die in matinee accident.
2. Handler never stated that she is alive. Maybe she is dead but in another situation.
3. Captain Widdershins was afraid of Great Unknown and he did not explain why. The possible reason of his fear is he didn't want such awful death as was his wife's.
4. Captain Widdershins didn't want Fiona to know about Great Unknown and perhaps, because he didn't want her to know a terrible true of her mother's death.
What do you think?

[Dante]

First things first, I've noticed this a couple of times lately, so let's clear it up.

This is a manatee:
www.manatees.net/manateeb.jpg

And this is a matinee:

an entertainment, especially a dramatic or musical performance, held in the daytime, usually in the afternoon.

The one referred to in Fiona and Friday's backstories is the aquatic mammal, not the cinematic entertainment form.

To return to the subject, this is entirely plausible. What TGG says is that... well, when Captain Widdershins first references a manatee accident, Fiona says that she doesn't think it was an accident. But Snicket says at the end of the book that Fiona's mother didn't die in a manatee accident. And those two statements imply different things; the first implies that Fiona's mother is dead, the second that Fiona's mother is alive. But it's really vague; I couldn't even say for sure whether a manatee was involved, whether Fiona was present or not, and whether even Captain Widdershins knew what really happened. I think this is a case where it's largely up to us to decide what we want to believe; given that, I think suggesting that Fiona's mother was taken by the Great Unknown is entirely plausible. It'd actually be kind of neat, since that's where Captain Widdershins, Fernald, and Fiona later end up.

[thedoctororwell]

I think that the "manatee accident" is something the Captain brought up so that he wouldn't have to speak much about their family's past, much like he did with Fernald. He likes to hide secrets under the carpet. However, the way Fiona criticizes it implies she has at least tangible facts to scrutinize - it doesn't seem to be something she just got from word of mouth. So either the Captain has gone to great lengths to make up a fictional death (including, possibly, false statements by third parties or fake documents), or either there's some truth to the lie : Mrs Widdershins, was, indeed, involved at one point in an accident with a manatee, but she didn't really die here and then.

We could also take Lemony's statement as some way to say "it wasn't a manatee accident per se, it was a manatee murder, as in murder by manatee" ; maybe an evil VFDer threw her in a pit of starving manatees at Anwhistle Anquatics (à la Lulu) and the authorities declared she had simply fell into the pit by accident. We can even argue the possibility of a manatee suicide ; we simply don't know whether the fake word is accident or manatee.

It simply fits with two many theories at the same time ; the Captain could be sincerely wrong about the nature of the death or actually lying to Fiona. The rest, as the saying goes, is up to Fanfiction.