I could be wrong, but I would argue the odds of any "poison pills" in the upcoming budget to be remote at best. Not because Harper can be trusted, but because the political landscape won't allow it. The Conservatives have shown their political tin ear before, a mix of arrogance and detachment, so anything is possible, but a provocation in the budget would be such a colossal error, it's hard to imagine.
Leave out the threat of a coalition for a moment, and you are left with the Conservatives basically forcing another election. Despite the false perception of "riding high" in the polls, I don't think many serious Conservative strategists subscribe to the folly of thinking an election is the answer. As a matter of fact, it's hard for me to see any scenario, wherein the Conservatives actually attain a majority, more likely the status quo or worse. Do the math, where exactly do the Conservatives extract the needed MP's to form a majority? A very real possibility that the Conservatives would lose seats in Quebec, this crisis and the insult, fresh in the mind of Quebecers. That simple fact translates to all hopes riding on Ontario, and apart from a final push into the Liberal heartland, the numbers just aren't there, if one is being reasonable. A failed budget, Harper takes to the hustings in Ontario, ground zero on the economy, and he improves considerably? That logic is beyond sketchy, holding on to what you have more likely, because the debate would surely get serious, and last time I checked, no matter the starting point, people don't generally reward parties in power, while the economy is crumbling. In other words, good luck putting your faith in flimsy polling, the simple facts will surely supersede any temporary comfort, a "sweep" would amount to a historical oddity, given the economic state. Imagine an election climate, wherein the government of the day is bombarded with almost daily poor economic feedback, smack dab in the heart of the recession. Then try to argue how that negativity helps the "hand at the tiller" party. Okay. If anything, I could cobble together a more realistic scenario for the Liberals wanting an election, real and present problems aside.
If you accept the likely possibility that the Conservatives are denied a majority, a real danger of a lessened mandate,then that result equates to Harper effectively being DONE as leader. The next election is Harper's last chance, the risks now are immense for him personally, which is why I think he will try and avoid an abrasive budget- he really has everything lose, and not much to gain, wishful thinking aside. Go to the people, because you poked the opposition again, resulting in a failed budget, in the aftermath of an abysmal fiscal update, and you're asking for serious trouble. I'll give Harper's team enough credit to realize the pitfalls, if they don't, it's simply astounding.
The only calculation for a poison pill budget, that makes sense to me, Harper thinks the coalition is clearly on the table and purposely provokes a series of events that lead to a new government. That is a far fetched strategy, but really the only one where provocation makes sense now. I'm operating on the assumption that Harper doesn't want another election, and I would suggest his moves of the past few weeks support that thesis. The optics of what we've since look more like damage control, and scrambling to hold onto power, rather than a party itching for another fight.
I guess it comes down to your definition of a poison pill. If you define it as anything that doesn't completely agree with the opposition point of view, I'm sure the budget will deliver that "hard swallow". If, however, you see a pill as a deliberate, ideological provocation, that tries to corner the opposition, akin to prior behavior, that appears unlikely from here.