Strange relationship

There are many situations one comes across in life where you have a strange relationship with the other person. One category of them consists of meeting people with whom potential relationships are possible but is not yet converted into a formal relationship.For e.g., interacting with a potential tenant, a potential in-law, etc. Sometimes, the relationship cannot even be defined as a 'potential relationship' category.

What about a tenant, showing the house to a potential new buyer of the place who is going to kick out the guy showing the house. What relationship could this possibly be called? It is just a strange relationship...