I was going to start my own question similar to this one because I have just encountered this in a piece of news on the NHK WEB EASY site:
(Not sure if they keep all the news available for long, but the link will work for now at least)
Having first checked some other explanations (1, 2, 3, 4), I found this answer and decided to post some links here and give the example above of what can also be considered a "concise use" of たり where you give just one example action (as opposed to at least two)
In this case, as I interpret it, the single action of マスクをしなくなったりする implies that there are other actions that senior citizens might be doing that troubles other people (I would assume not washing their hands, not practicing social distancing, etc.), and we actually see one of this in the examples in the subsequent paragraphs:
I would also like to point out that if you follow those links I gave above, many people are quite strict in their views on this grammar, while some provide examples of grammar books that acknowledge this increasing flexibility as early as in 1970s.
And so, now we even encounter it in official news, albeit for foreigners. Or maybe I should say "even though" because this is where I would partially agree with those who try to stick to the rules: since this source is aimed at foreigners, with what is called やさしい日本語, I would personally expect them to use regular beginner/elementary grammar constructions, i.e., ～たり～たりしない in this case. If they are doing it consciously, even in materials for foreigners with only basic Japanese skills, it might be a proof that such flexible use of たり is actually quite common