The ironic part is that it appears to have been BBC America's own shop
that were responsible for the copies being sent out.
Oh and the BBC have decided to try bribery to avoid the information beoming widespread.
"We understand that a small number of US fans have received in error their DVD edition of Series 7 Part 2 early. We respectfully ask those fans not to divulge information or post content publicly so that fellow fans who have yet to see the episodes do not have their viewing pleasure ruined.
If everyone keeps the secrets safe until next Saturday we will release a special new clip featuring material of the Tenth AND Eleventh Doctor!"
So it's either a clip they were already planing to release or they know that human nature being what it is they won't have to release anything.