It must feel like a safe strategy for them but as the letter makes clear, it's a shitty strategy from an ethical perspective - but from a winner take all perspective it looks better I grant...
I am just unsure it's all upside for them - is this convincing people to switch allegiances, like will people change their vote due their pushing of the niqab and refugee issues? I'm thinking this is better for them on a conservative turnout/"rallying the base" perspective than it is as a conversion attempt on liberal/NDP supporters. The fact is Canadians very much DO rank these issues near the bottom of their priority list, so it's power to win new votes for them may be small.
It also can rally the base of NDP and liberal supporters, and with stories like this coming out:
We may find the backlash to their politics here undoes their short term polling gains.
We will have to see on election day - only then will we know if this was a political smart approach for them or one that had a poison pill inside... And the answer here may also be province specific (ie good for them in Quebec but a non factor or negative factor elsewhere)