I stumbled on this information in the 2022 Lonely Planet guide to Eastern Europe (which isn't really recommended because it attempts to cover over 20 countries in 500 pages, but I could tell that things like hours of operation had been updated). Estonia requires pedestrians to wear reflectors if they're out after dark. The guidebook says the police in Tallinn are enforcing this and assessing fines.
The website below provides some background information. It has a lot more detail than LP. Since this seems to be the country's official tourist-information website, I assume the details are correct.