Flarum doesn't support it out of the box, and I don't think an extension exists for this at this time. But technically it should be feasible.
If an email provider supports aliases, like with +
, anyone could create any number of forum accounts by using a different alias each time. This will work on any vanilla Flarum installation.
If an extension implements re-usable identical emails, some other extensions and Flarum features might break because email is expected to be unique, though an implementation might be able to use hidden aliases behind the scene to identify an account, and strip that alias when passing the email address to the mailer.