They blended two trick questions for which the normal answer is positive, among a long sequence of questions with normally a negative answer. I fell into the trap and answered no for the two 'should have been yes' questions. I had to reapply for the visa. I got the visa eventually.
This year, I am applying again to attend ICSE 2009 to be held in Vancouver next month.
I was extra cautious this time, lest I make mistakes. But to my surprise, I found that they have changed the visa form. Now, they no more have an entanglement of positive and negative questions.
They decided to change the form after a lot of people made the same mistake. Or maybe its just me initiating the change !!!