Here's something that won't shock a single member of the Rihanna navy. The singer's already-fraught-with-problems Diamonds tour -- which saw two canceled dates in the first week -- has hit another snag, this one at the border of Michigan and Canada.

Marijuana was discovered when the caravan of tour buses was pulled over.

Ten buses were stopped at the Ambassador Bridge, reports TMZ. One of the border patrolmen got a whiff of weed and an instant search of the buses was ordered.

Drug-sniffing canines uncovered the culprit, who had pot on him. He was cited with a civil penalty.

As for RiRi? She was not on any of the buses. But she's somewhat guilty by association...and the fact that she does not hide her love of the green stuff.