Mashable's Chris Taylor talks about the problem of misdirected emails. A good read and it helps to expose a real issue that I don't think many people stop and consider.
I'll add my own questions here. What if, because of this, a sender is exposing PII (personally identifiable information) to a random third party? Couldn't that lead to some sort of legal liability at some point? How does a recipient stop emails like that? Are you, as a sender, putting a "this is not me" link in your transactional messages?
I have a bunch of spamtrap domains. One of them is a typo variation of a very popular ISP domain. The number of misdirected order confirmations and password reset requests it gets is ... staggering. If I was a bad guy, think of all the bad things I could do with that information being fire-hosed directly to me. I could probably take over hundreds of Instagram accounts. I could probably cancel or redirect orders from online stores. Or worse.
More reasons why you can't just assume that any email address given to you is correct.