I have a private repository set up as betty. My username is asgillmor. I publish from my home box where my login is 'alex.'
Bitbucket is associating the bitbucket user 'alex' aka 'Alex Surachi; to my checkins for my private repository.
As you can see in the attached picture. I am logged in as 'asgilmor/betty' but the checkins are for Alex Suraci / alex, who did not check in any of this code and I hope does not have access to this code.