Opting recipients out of "transaction" operational emails

We're using the operational email setting when sending transactional emails, but still want to accomodate those who email back saying they want to opt out of them.

If I create a attribute of "Transactional Opt Out", give it a value of "True", assign this value to these recipients, and filter by this in the smart campaign with the operational email setting turned on, will these recipients be excluded? Or will this filter be ignored since the operational setting is turned on?

Alternatively, does anyone have a better solution for this?

Thanks!