DEAR AMY: The writer "Perplexed" states that she is a professional in the same office as "Mary" and "Sue." Mary was secretly keeping tabs on "Sue's" lateness, etc. Perplexed should report to management or HR what she sees as a potential hostile work environment for Sue. She should not speak with Sue about the issue directly. Management should be made aware of Mary's behavior and take steps to ensure that Sue is not being harassed and to inform Mary that her behavior is unacceptable.
Retired HR
DEAR RETIRED: I understand your perspective. But wouldn't it be easier for "Perplexed" to simply say to "Sue, hey, FYI. Mary's keeping tabs on you. You might want to work on your lateness." Then if Sue has an issue with the dynamic, SHE can report it to HR.
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The Principle of Least Interest: He who cares least about a relationship, controls it.