I would typically make an email alias for a company that was [company-name]@my-domain.com and use that as my contact email for correspondence with said company.
So, I was doing something with the DMV online - and I created the alias "dmv@my-domain.com" to communicate with them via...
They sent their lawyers after me and sent me cease and desist letters telling me that my use of dmv@ was a violation of their copyright and that I would "confuse users"
I tried to explain to the DMV (yes dept of motor vehicles) how ridiculous this whole thing was and that the email address was for their use only - and that as a state agency, they don't have a consumer brand and that anyone with the initials of DMV, like David Michael Vincent would be using DMV in their emails etc...
They persisted and were annoying enough I just deleted their alias...
This has the side benefit of making it obvious who's responsible for selling my email address and makes it easy to ameliorate being signed up for unsolicited email lists by burning the email address. (A popular tech journalism outfit has been the worst offender in recent years.)