89% of charities issue inappropriate receipts according to statistics from the CRA when they audit charities. Other than non-filing the T3010 this is the greatest reason that charities face revocation. Here is my paper that I delivered to the Ontario Bar Association (OBA) Institute 2011 entitled Top Receipting Concerns for Canadian Registered Charities.
Here is the article entitled Top Receipting Concerns for Canadian Registered Charities.
As noted in the paper here are some additional resources: