Complaint and SOP Adherence
Was there a complaint from the consumer first? Secondly, as opined by professionals above, if there are clear SOPs (Standard Operating Procedures) against such visits, why unnecessarily create a precedent of sorts? If the visit is for personal gain or if he is chasing or stalking a female consumer with improper motives, then you can certainly issue a warning letter.
Counseling and Investigation
The first stage is verbal or oral counseling by his immediate superior or Head of Department in your presence. It is possible the employee may be new to the job role and could be a bit over-enthusiastic. So, first find the facts, counsel him, and ensure that this is not repeated. If he is a serial offender, then the matter is different. Please provide clarity first.
Best wishes