To echo what Brendan says above - if, as it seems, it is an isolated incident then there's no real need to get too worked up about it. If it was me (and it was in the past with a stockbroker who sent me another person's trade receipts) then I would just return the material to the institution and, perhaps (although I didn't), inform the individual involved in case they want to take the matter up with the institution. Mistakes do happen and, as long as they are not evidence of any systemic process failures or anything else untoward, should be excused in my opinion.