[Dr. Franklin]

Is there any good reason for that?

I think it's standard for residential property. Anything higher than that is considered commercial and may require a hearing before the local zoning board. The idea is that they are protecting property values and their tax ratables. A six foot fence won't keep deer out of the back yard and garden either.

[Savage Beast]

Seems like a silly rule to me. Why not let people build fences as high as they want?