Auto-Rotate checked on by default: How to achieve this

Ok I think this is the correct section to post this
 
Hello,

I have a PDF document where I have a mixture of portrait and landscape pages all in the same Paper size - letter. It prints alright, auto rotate is checked by default but some of our clients complain that it shrinks the landscape to a vertical orientation.

I wondered if its possible to Force the Auto Rotate option to be checked by default or even locked, for those not-so-tech-savvy clients. I have Acrobat Pro.
 
I hope my point is clear enough.

Please help.

Thanks