I think it's likely that Flickr has a way to recover the data but the front line...

InclinedPlane on Feb 2, 2011 | parent | context | favorite | on: Flickr Accidentally Deletes a User's 4,000 Photos ...

I think it's likely that Flickr has a way to recover the data but the front line support personnel don't, and they don't want to have some dev spend a few hours to fix a single customer's problem, even if it was Flickr's mistake.