One company gave me a free version of their paid offering because my email address was me@them.my.domain, which triggered their "is an employee?" check. (I reported it to a friend who worked there, but they didn't prioritize fixing it. Lasted a while.)
Uber tried to make me change my email address because:
> As much as we appreciate your enthusiasm, and value you as a loyal rider, I do need to ask if you could, please, update your email to something that doesn't use "Uber" in it, as that's technically a trademark violation.
> I apologize for any inconvenience that may cause and thank you for your cooperation. If I can help further with making that change to your email, please let me know.
They backed down, but it was pretty amusing to get this email in response to a totally unrelated one.