Correct clamped quick release lever direction Which direction is the correct way for the QR lever to point when closed and why?

I have found both upwards and backwards on different parts on the SRAM website even for the same forks.

 

I have also been partial to many heated debates, in addition to being exposed to very opinionated bike mechanics’ views around this question.

Personally I prefer backwards, thinking that it has fewer snag opportunities and the aesthetics of the logo work better.

The rear axle potentially has even more view points.

I’m specifically interested in mountain biking. You see the forward clamp fairly often. Whilst neat, this tends to collect grass and shrubbery as you go.
There is only really one rule - position the lever such that it is protected from being opened by hitting or snagging on something.

Straight forward or down is not a good idea, obviously. A rear lever pointing straight back is not good either as a collision with the front wheel of a bike close behind could potentially open it. 

Rear levers protected between chain and seat stays is probably OK, maybe more vertically behind the seat stay is better. Front levers angled back and up behind fork legs is probably good. 

Otherwise position the levers wherever is convenient.