2014-01-25:

LL tagged this issue as 'critical' so I am a little bewildered as to why a fix for this hasn't been out yet. Therefore, you're all getting helicopter updates this weekend.  The Alligator, Hind and Black Hawk are done, the Viper and WAH-64 are next.

And the six of you who read the update notes and manuals will notice that you can turn off the anti-littering self-delete by selecting"AutoDel" from the options menu. This option is intended for those who wish to display the aircraft on land they lease or group owned land, where they are not the technical landowners.

This feature will be coming to the land vehicles shortly as well.

2013-11-27:

As was brought to my attention, some OCS vehicles were registering damage upon sim border crossings. After investigating this issue, I determined that the vehicle was colliding with the pilot themselves upon crossing, which is obviously unwanted SL physics behaviour, and filed a bug report with Linden Lab.  They have been able to reproduce this bug, categorized it as "Major" and have triaged it to MAINT-3517.

So a fix is on the way. I'll update this when I find out when it will be deployed, most likely to the RC channels first.