If he said anything that wildly inaccurate in the house, I'd imagine the Hansard would be full of interjections from other MPs and perhaps a description of Mike Harris attaching a muzzle to the man's jaw.
Unless the number was so jaw-droppingly wrong that it was ignored by everyone else, and treated as an obvious error. After all, the issue was the decision to sell. The amount it cost to buy the land had only a slight bearing to what it was possible to sell it for; at $100B it would not have sold. So perhaps this is simply a case of the opposition staying focused on the matter at hand.
I would have thought that the number being treated as *accurate* would be what would have gotten the opposition riled up. After all, it would be a very easy argument to make with the public that it was being sold on 3 cents on the dollar.
If you want to go further with this, I suggest trying to find proof that the land costs *could* have been that high ANYWHERE in the area that the 407 was built in. For example, a quick search got me the following from York Region in 2008:
"The Commissioner of Corporate Services be directed to complete the acquisition of approximately 29 hectares (71 ac) being described as Part of Lot 34 Concession 6, Town of Whitchurch-Stouffville, for $330,000 plus associated land securement costs of $30,000 for a total acquisition cost to the Region of $360,000".,
Now, this comes to $10,000 per hectare. I'll grant that the 407 land acquisition may well have had to buy a wider strip than the highway itself occupies, but even if we say that they bought a 1 km wide strip, you'd be looking at 6800 ha total, meaning that the per-ha cost would be over $14M/ha to reach $100B in total, which is 1000 times these costs. NONE of the lands in the 407 corridor would have been developed enough to account for that kind of a difference.
Extraordinary claims require extraordinary proof.