Now that I think about it, I wonder if flights between Canada/USA have different rules?
yes, there are. There are severe penalties for violating international restrictions which often cover agricultural products ie fruits and vegetables. A stray orange can result in denial of access to preclearance programs in future, or even fines. Unfortunately when this is pointed out many still decide to violate the rules. Personally, I would not take the risk
For those using preclearance programs and crossing international borders, there is a zero tolerance policy when flying for any food products.
As to flying with chocolate - I regularly bring 20 kilos or more when flying from Germany and have rarely had my bag searched. (I fly at least once a week every week of the year) I also carry several bars when travelling within the US in my suitcase and rarely have a TSA notice that it was searched.
While it MAY result in an additional search of the luggage, it does not guarantee additional search (especially not if American candy bars - think 20 bars of Lindt or similar size/density, as opposed to five American candy bars)