It is true that in some states, you could lose property if you've given up the use of it for five to seven years, and if the neighbor were to go to court to get a judgment to that effect. This is called adverse possession, or in the case of access to property, a prescriptive easement. However, giving permission to the neighbor to use the property "defeats" a claim of adverse possession. I would not trust oral permission, however. Best to get state the agreement clearly in writing to ward off a later war of the words.

To avoid all possible sticky wickets that may spring up around the property ownership issue, draw up a written permission for the neighbor's fence that:

• clearly defines the actual property boundaries
• clearly defines the location of the fence
• states that the fence belongs to the neighbor,
• grants the owner permission to place the fence there, and
• clearly states that the location of the fence does not alter the boundary lines.

You and all owners of the fence should sign the agreement. And it would also be wise to treat the paper with legal deference: Get it notarized and be sure to keep a copy for your records. For added protection, you can file a notarized copy of the agreement with the recorder's office in the county where your property is located.