2008 Myanmar Travel - North Myanmar Travel.
From one town to another, there may be check-points to collect tolls. One check-point was manned by soldiers with guns. Most check-points were manned by people in civilian clothing. At one check-point, I took a picture of a billboard selling Ko Ko motorcycles and it had a picture of a "crocodile" similar to the "crocodile shirts" selling in Singapore. The check-point man in this rural town demanded to know why I was taking photographs. I could not understand him. "What is his objection?" I asked my guide. My guide spoke to him saying: "He has permission to take photos." So, there was no more problem.
2010 Europe Travel - Italy/Switzerland & Switzerland/France border check points warning
In developed countries like border crossings between Italy and Switzerland and Switzerland and France which I had been last week, the tour manager specifically warned us not to take any picture or crack jokes. Otherwise, the tour bus and baggage would be thoroughly inspected, delaying our travel by several hours. So, this was not a situatin unique to Myanmar.