I am very intrigued by these replies. They are obviously accurate as several of you say the same.
I now live in Puerto Plata and must have travelled by publico from Sos?a a hundred or more times over the last four years. With a couple of exceptions their route has been via the Stadium, the Hospital, La Javilla, Parque Central, and then directly back to the Hospital. In other words, nowhere near Tropical or La Sirena.
Do they now make a detour from Parque Central on the return leg to take in Tropical?
The two exception were when the passengers agreed with the driver to go straight into the centre of town from the Stadium (by-passing the Hospital). I wasn't consulted on either occasion being a mere gringo!
So are these publicos going to or near La Sirena a result of similar prior agreements or has the normal route recently changed?