Turn off Email Tracking - GDPR

Hello, regarding GPR and the fact that we have to obtain explicit consent to track people (as a global company, we're assuming everyone is in the EU for simplicity), we are operating under the assumption (backed up by my legal team) that we need a way to disallow the tracking of email activity - and importantly, this needs to be differentiated from the tracking of website activity (through Munchkin). Can anyone speak to this, with examples of how you're handling it?

The fact that I reached out to Marketo support and they were essentially shocked that anyone was asking about this, implies to me that we may not need this functionality at all, but my legal team seems quite sure. To that end, I don't expect to receive a wholly satisfactory answer here that I could then use to sway my head of legal, but perhaps there's something more to this and I wasn't clear with Marketo when we spoke.