For those that have NOT rotated their tires (I know BMW does not suggest rotating tires), can anyone tell me which corner tire wears out faster?

A friend of mine took his BMW for service and they made him buy all 4 new tires since one wore out faster than the other three. They claim that "the iDrive makes that one tire wear out faster and that you need to have all 4 tires equal depth". I smell BS.

So now, I am asking if anyone noticed any tire wearing out faster than the other three.

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2004 Porsche 911 C4S X51, Seal Grey / Black
2006 Porsche Boxster S, Guards Red / Sand Beige
2008 BMW X5 4.8i, Black Sapphire / Saddle Brown
2001 Audi A4 1.8tq, Laser Red / Black, APR Stage 2, H&R Coilovers
2002 Suzuki GSX600 Katana, Yellow