Importing users fails on valid email address

Would it be possible to update the import rules for email address validation? I’m supporting many groups who are signed-up via the import page, and I tend to use the gmail ‘+tag’ feature so I can separate out the emails which get sent to each group via MailChimp. So for example I’d add myself to the import list with an email address of ‘my.name+group1@gmail.com’ for Group 1, ‘my.name+group2@gmail.com’ for Group 2, etc. But s2 refuses to import that type of address – the error is:

The following errors were encountered during importation:
Line #1. Invalid Username (my.name+group1@gmail.com). Lowercase alphanumerics are required.

See the top answer to this for a fairly accessible list of valid characters in the local part of an email address…

Thanks,.