The other time was frightening. I was hired by a DC real estate management company to photograph some of the buildings they managed. Mostly office buildings, but there were a few embassies, too. For some of the embassies there were very specific rules. One was the Saudi Embassy. I could only photograph from the street, and it had to be done at a certain time of day. The company I was working for cleared everything with the embassy secretary, and I was set to go. I arrived at the appointed time, and began working. Within 3-4 minutes, about 6 guys, with guns out, were running at me, screaming (I can only assume it was abusive, as it was in Arabic). They grabbed my camera ( an SLR) and had me lay on the ground. A few minutes later, a few DC police cars arrived, as well as a handful of big black SUV's from the State Department. I explained to the cops, and State Department guys, what I was doing. At that point, the Secretary came out, apologizing because he'd forgotten to tell his security guys to expect me. I was allowed to finish, but 2 of the security guys followed me around.
Seems to me somebody should explain to those guards the way things are here in America, before there is a serious "incident".
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.