To clarify, over the last 15 to 20 years I've noticed them and benefited from these wind breaks. I have no idea about the last few years. While I've been many times, most recently it's only at enclosed restaurants and in the evening and night.Allow me to modify "plexiglass" to wind barriers in general. It's been a while and I don't want to exaggerate and memory is a funny thing.
Bear mentioned Tuva which has tall glass "wall" on their patio, I recall specifically a bar/restaurant at one of the Kite Beach hotels that had plexiglas, Mojitos IIRC has roll down bamboo shades, at one point a couple or so years ago other Los Gringos or Lazy Dog had a (plastic?) windbreak and Lazy dog and I think the adjoining business had curtains. I can't swear to it but I've also sat near a wood or bamboo windscreen on that beach. It's windy as hell some afternoons and that's mostly why I rarely venture there. It seems to me it's been a couple, maybe even 3 years since I was there last and I don't miss it a bit lol