>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.

    [email protected]       probably a legit address
    [email protected]    probably an alias

at that point you can either not send to that email, or if you're extra evil, try to frame another company (try sending to [email protected] or [email protected]). it's not even that hard to do because 99.9% of people don't use custom email domains.

Email marketing is a numbers game, I doubt anyone is wasting time looking at individual addresses.

And even if a script could easily process addresses in an automated manner, it might be actively harmful to a marketer to do so. People who intentionally use disposable addresses are probably less likely to respond to email marketing and more likely to take actions against the marketer.

It's trivial to write that script, but not any more trivial than just generating lots of common_name@common_domain email addresses. Once you're willing to spam emails that didn't opt-in even to a list that you bought, you've entered into very shady territory.

Email providers should make it easy to create a (temporary) alias. E.g.: [email protected]