[tsewlliw]

A witty saying proves nothing. -- Voltaire

Just as a general rule in conversation, invoking so-and-so's law or this fence isn't a productive tactic. Instead, ask the question that wisdom suggests you ask, and for this bothersome fence in particular, keep in mind that you are weighing an unidentified consequence against a proposed benefit, and at least endeavor to expend some of your own effort on suggesting what the value of the fence might be or how one might go about finding it. You may find some of that effort has been undertaken and that failure has not been shared.

[ska]

> invoking so-and-so's law or this fence isn't a productive tactic.

Not true. If we both are familiar with the concept, saying "Consider Chesterson's fence" conveys a lot of information. If we aren't, chasing down the reference will almost always result in a much more articulate version of the concept than whatever you or I would come up with on the fly.