[dredmorbius]

There is a potential criminal risk if a relationship can be construed as nonconsensual, coerced, or quid pro quo.

More generally, there's a tremendous civil liability, both personally to the principles involved and the firm, through such activity. A liability which may be entirely independent of the apparent (or actual) consensuality at the time, and which might be filed by non-participants (e.g., other employees perceiving sexual favouratism or discrimination).

A principle function of a corporation is as a risk-externalising, and limiting, legal structure. (This is literally stated in some forms of organisation, as with an LLC: limited liability corporation.) The principle job of management and oversight is to maximise the reward-to-risk ratio.

Company founders openly and documentedly treating the employee pool as their personal coital resource is a risk in the extreme.