It is quite rigid and I have never heard of any exceptions to the rules. That said, I have used it twice, had no issues, and got the check both times within a few weeks of my request.

With this rebate, my diesel worked out rather well financially... $4,500 Eco Credit, $3,000 off MSRP dealer discount, $1,000 CCA rebate, $1,800 off my 2009 taxes, and I got the sales tax deduction without itemizing (temporary change in tax law). Roughly $11K off of a $61K vehicle, ordered exactly as I wanted it.

It was a good time to buy, IMHO.