I received a letter from former my employers to my home address. It contained highly sensitive personal information. It was marked "private and confidential" on the letter itself, but not the envelope.
My name was missed off, so showing through the window was just the house address.
It was opened in error by the householder (not me) assuming it was a twist on "To the Occupier"
Would you be bothered that a highly sensitive letter had been misadsressed in this way, or would you shrug your shoulders and think "accidents happen"?
(If it's relevant: HR aware I am not the house holder; no harm done as householder privy to info in letter, though not a close family member. Would have created an uncomfortable situation all round if this hadn't been the case.)