We recently completed a camping (with a large travel trailer) trip through Northern BC, Yukon and Alaska. It involved entering the US twice, Poker Creek and Dalton Cache.
The CPB member at Poker Creek asked no questions about food, Dalton Cache did, specifically citrus. He took the oranges.
Given we were towing a trailer, had three kids with us, we had a lot of food. Citrus was the only concern.

Some the of the friendliest CPB members I have met. The Dalton Cache member became a tour guide adviser, gave us maps, told us where to find grizzlies feeding on salmon, campgrounds etc.