> It is valid to remove +suffixes from email addresses (e.g. john+doe@example.com → john@example.com)
It is always valid to strip the +suffix. People won't like it, but the RFC says that part is always optional.
[1] RFC5321 "the local-part MUST be interpreted and assigned semantics only by the host specified in the domain part of the address"
"Consequently, and due to a long history of problems when intermediate hosts have attempted to optimize transport by modifying them, the local-part MUST be interpreted and assigned semantics only by the host specified in the domain part of the address."
No, it most certainly does not. If you think it does, please point to the relevant section in RFC 5321 or RFC 5322.
I've only had a single (government) organization refuse to leave the dot in my address, so I had to special case them.