I have my own domain name, so I've started using address aliases for different things. There's no way that they can get around that.
unless you use high entropy aliases, there's nothing preventing someone from filtering out all the emails with "uncommon" domains for secondary examination. at that point, you can manually ascertain whether the email address is an alias or not.
firstname.lastname@example.org probably a legit address
email@example.com probably an alias