The briefing note for Prime Minister Stephen Harper lends credence to one of the Canadian retail industry's biggest complaints.
The note says the guards don't bother charging for lower-value goods, and sometimes are too busy to collect taxes and duties on higher-value items as well.
The document was obtained by The Canadian Press under the Access to Information Act.
A spokesman for the Canada Border Services Agency acknowledges that managers at busy border points sometimes have to adjust priorities, between revenue collection and catching forbidden imports or illegal visitors.
Cross-border shopping has risen as the Canadian dollar hit par with its U.S. counterpart, but economists say the recent fall in value will dampen the number of bargain-hunters heading stateside.
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