Suspension of civil liberties in response to political unrest is not an uncommon response. We've seen it in the US. That doesn't make it right.
I'm not Canadian, so perhaps I shouldn't arm chair quarterback Canadian history, but you asked what I would do.
I'll respond to a similar scenario that hits a lot closer to home for me: would I have supported the detention of hundreds of Muslims after 9/11, without any evidence they'd committed a crime?
Absolutely not.
And on that basis I feel perfectly comfortable saying that the detention of 500 people in Quebec, without any evidence they'd committed a crime, was wrong.
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Edit: I'm "posting too fast" so I'll respond briefly here to the posts below:
> so democratic that we have allowed votes on separation over the years
Canada hadn't allowed such votes before the October Crisis. The first referendum on Quebec sovereignty was in 1980.
Holding a referendum in 1970 would have been preferable to the violence and the suspension of civil liberties, but only the [mostly anglophone] government could have called such a vote, and it wasn't done. Not then, and up to that time, not ever.
So when you say that the Quebecois were trying to separate "by force, without vote", remember that such a vote was not an option available to them.