Just to let folks know, Flarum will now block new registrations using what it determines to be disposable e-mail addresses. My hope is this will very effectively deter trolls and spammers who rely on such e-mail services to stand up thousands of accounts very quickly, where now they will need to go and register full e-mail accounts.
It's not perfect, but it should get rid of the worst of the noise in combination with other measures now in place.