The emails are legitimately from Ticketmaster. Ticketmaster, as a US company, is apparently obliged by the IRS to ask everyone it sends money to anywhere in the world to fill out the form, regardless of where they live. The form simply asks you to certify that your Canadian address, which they already have, is your permanent residence. Much as I am no fan of Ticketmaster, this certainly was not their idea. The US has long had a fairly oppressive theory of its right to intrude on extra-territorial business dealings when any US entity is involved.
StubHub actually wanted to withhold income tax on sales to American purchasers. Which is why I sell extra tickets through the team website now.