Privacy is a major concern nowadays.
Sensitive info need to be tokenized or masked while leaving functional info unchanged during business analytic or conducting system tests.
Nevertheless, a function might be uniquely provided by a particular individual within the information sample. In this case, even if the identity is masked, the functional aspect can also traced back to that particular individual. This is something like weak hashing function subject to reversible attack.
This is the situation to watch out and need to voice out the limitation to data subject and data owner.