I was just discussing this with a colleague and his comment was that he "just couldn't understand why it's so hard to get a straight answer." Then the proverbial 'light-bulb' came on and it all seems very logical:

Border Agents now have complete histories of every traveler right in front of them. Who is going to risk a career to let someone pass? What if they let me in and something happened? I wouldn't let me in if I was in agent's shoes.

The solution is to fix the policy, but, like the boss in Dilbert, management is paralyzed by fear. Who is going to, again, at risk to career, come out and say "the effect of the current policy is a new slogan: 'Canada - Closed for Business!'"

"Operational Bulletin 389", the 'answer' to growing complaints from Canadian tourism interests, is a perfect example of this paralysis. Soon every state will require some minimal jail time for 1st time DUI - so what is the point of waiving TRP fee for 'single DUI, no jail time?' Just another pointless piece verbiage used to cover backsides while telling constituents "I did SOMETHING..."

Here is an example of why people are confused - I just found this gem on a sport fishing site. I'm sure the poster is reporting what he was told, even though it was a complete distortion of the facts:

"It is my extreme pleasure to tell everyone that I was honoured last Friday to be invited to a conference call from the Federal Minister of Citizenship and Immigration Canada who announced to us all privately that he signed into law last Friday, effective March 1st 2012, a new program for the border crossing issues involving minor misdemeanours.
This involves particularly, but not solely, DUI’s. These laws have now been relaxed making entry to Canada much easier with a one time minor offence.

He told us that anyone who is a single, one time offender of any misdemeanour including DUI, bar fights, assault, bad checks, etc. and who did not serve more than 6 months in jail will now be automatically allowed into Canada and not turned back with NO FEES required and they have also made the rehabilitation process much simpler, quicker and easy to fill out now too.

The Minister apologized to all of us in the tourism business and said it was never their intention for the law to go this far. They never meant for one time offenders, who made a single one time mistake sometime in their life, to not be permitted into Canada and he was changing this law to be effective right away, as of March 1st. "

It's a shame, because policy change given 'off the record' would go a long way toward fixing this problem.