Not true, you can only get away with not having chains on AWD vehicles only if you have snow tires on all 4 wheels (R2 requirement). This is directly from the CalTrans website.
And if it’s a R3 requirement, EVERY vehicle must have chains on, no exceptions.
But virtually all the vehicles I have had in the last 30years have OEM tires with a “M+S” (mud and snow) and those are good enough for CHP. So with AWD no chains in R2 conditions.