Correct me if I’m wrong, but #1 only really applies to M:C and this limitations does not exist in M:C. While your Method ID session will expire, your M:C session / session ID does not.
Regardless, Mahlon you make a good point that our users may use different browsers for using vs. customizing Method and Matt you also make a good point that multiple users may use the same Method ID for signing in to different accounts at the same time (
especially for customizing). I have created a feature request ticket for this. Hopefully our development team can work out a way to make this happen.