The Concept of Moin

Well if we assume a Moin was gonna Moin Moin, then other Moins hearing the Moin Moin moin would have to decide how to reply, either by Moin Moin or a simple Moin, while you have to note that a Moin's Moin Moin might end up in a longer discussion, a simple Moin spoken by the Moin would result in no further discussion. A common misconception among tourists is, that Moin Moin is the standard procedure, however locals know this to be false, a single Moin is the most common, as a Moin Moin would, as explained above, convey a different meaning and attitude.
This misconception is also why articles advertised to tourists always say Moin Moin, rather than the, as we have learnt, more common Moin, while the indigenous inhabitants of this land prefer a single Moin on their articles, such as doormats or welcoming signs.
In general I can advise you to not go too far and go from Moin to Moin Moin, unless you know the information transported with it.