> not everybody has an email client set up that works with mailto: links Mostly bad chrome configs where you need to browser plugin to lauch chrome. >I doubt

> not everybody has an email client set up that works with mailto: links Mostly bad chrome configs where you need to browser plugin to lauch chrome. >I doubt that DMARC/DKIM/SPF are actually deployed as widely as OP thinks, and excluding users based on some (to them) obscure/unknown feature of their email provider is bound to generate frustration. We're at about 30% with DMARC and SPF being deployed in about 65% of email servers. That said, a lot of the really big ones (google, MS, etc...) are in the 30% so are a lot of control panel hosts. Where the slow uptake is, as always is corporate IT departments. Doing the whole DMARC/DKIM/SPF dance isn't hard to do and really puts the clamps on spoofing.