I regularly receive emails sent to a person that enjoys using my email to subscribe to spam. I've also received stuff from another that used it for school and even their bank account.

And if you think verification does it, someone used their phone number and my email to register to Uber. I'd receive all their invoices and stuff. I couldn't log in because that needed phone verification. And it took quite a few rounds of Uber tech support to get them to remove my email.