commit tags dont validate ownership of email address

nathan@nathancahill.com is on my team, but if i set my email in get as nathan's (eg git config --global user.email "nathan@nathancahill.com") and commit bitbucket accepts this fine (even though i am logging in via my account) and then when the commit happens it looks as though nathan made the commit on the commit history, not myself.

Granted this is with git - so you may not be able to do anything about it, but it leads to some odd behavior if i have a global email address in git as "x@gmail.com" and commits with my "x@easypost.co" account show up as commits from "x@gmail.com"