Increasingly you get led down an endless paper trail of showing documentation, code reviews & ccra is now in the business of sicking auditors on claims to aggressively deny them. Wasted time & headaches.
Go to an info session to find out exactly what CRA's eligibility rules are. It is not that difficult to apply. Generally I have found their attitude to be "the money is there and we really want to give it to you -- because it comes from the taxpayer we just need to do due diligence that what you are claiming is in accordance with the tax act"