For reasons including the potential for sexual harassment allegations, consider a policy expressly forbidding romantic relationships between supervisors and employees. Many workplaces have policies forbidding romantic relationships between any employees, but this is primarily for productivity reasons. Supervisors may find this to be a constant battle that results in more secrecy than in compliance, and in terms of sexual harassment legal claims, the employee has no grounds for a suit unless the harassment comes from a supervisor, or no action is taken against reported harassment. Precedents include Colbert v. Georgia Pacific Corporation, Wal-Mart Corp. v. Davis, and Burlington Industries v. Ellerth.
Understand the definition of "supervisor" - the role does not have to be in the recognized hierarchy of your institution, but can be anyone who has authority over the employee - so someone who schedules shifts, conducts performance reviews, coordinates routes, and so on - all of these people and more may be considered "supervisors" in a court of law. In some cases, this is why companies simply cast a net ban on all intercompany romantic involvement.
Basic communication policies should be written and enforced as well - for example, daily, weekly, and/or monthly reports are due at specific times. Meetings, where agreements aren't documented in writing, should be followed immediately by emailed summaries or meeting minutes with phrases like, "per our conversation…" This, in particular, doesn't have legal ramifications, but it makes communication crystal clear and establishes a pattern.
What does that mean for the company? Documentation. Effective communication so that everyone is aware of problems and can address them before they grow. Lack of communication creates confusion, lack of clarity and direction, ill will, and eventually, poor work product and frustration. That might lead to bad blood, termination, and lawsuits. Keep communication consistent and transparent from the beginning.
Employee and supervisor communication policies are vital for the longevity of your company. Well-enforced policies will prevent costly legal problems and productivity concerns.