Another thought. In the USA, how does an overflying pilot know when to change to 126.7 if there is no way of him knowing that he is about to fly through the circuit of a strip?
In UK we have "safetycom" (135.475) for operating at locations with no allocated frequency of their own. In many cases it's pointless calling, because even if another pilot hears the call from an aircraft lifting from an unmarked strip (or helicopter landing place), it may mean nothing to him. If the place in question isn't on aviation charts he might well not recognise the name or the relevance. He may also hear irrelevant and distracting calls from other aircraft operating many miles away. We usually have other more relevant (or mandatory) frequencies to monitor.