Roles in Features: Are they always imported in alphabetical order?
Roles being imported in alphabetical order has been my experience, too.

But counting on autoincrement IDs to be consistent between multiple sites is never a good idea.

I recommend, instead of relying on the autoincrement IDs to be generated in a particular order, to avoid using autoincrement IDs.


For Drupal 6 and Drupal 7, the Role Export module turns Role IDs into hashes of machine names, so they're consistent from site to site, regardless of import order.
For Drupal 8, work is in progress to eliminate autoincrement Role IDs altogether.