I just checked file spanning using the "Media Browser" on the Mac Version of Adobe Premiere Pro v.6.

I guess, many do not come from cards directly but backups made on hard disks. Big surprise: With Mac and Windows-formatted disks the "Media Browser" will not allow to show files in the AVCHD-View option. When files are coming from a Dos-formatted disk (the disk I use is NTFS), the Media browser will automatically switch to AVCHD-view mode when you click a .mts file in the stream folder. Not before, i.e. when you click PRIVATE or any other folders. Spanned files seem to import correctly.

But on Mac-formatted disks, spanned files are not correctly imported, because AVCHD-View mode seems not possible...

So when you use a Mac product on location with mac formatted disks for backin up your cards, you seem to loose the ability to correctly import spanned files even on the Mac version of Premiere Pro 6....