Examples I've encountered:
* In a mall touchscreen navigation kiosk, an ad is shown when you first wake up the device by touching it.
* At multiple points in the McDonald's self-order touchscreen kiosk flow.
* On Starbucks screen menus, the whole menu is periodically replaced with a video ad, forcing you to wait until its end to finish making your choice.
> You also don’t have ads on at the airport timetable screen.
In the biggest international airport in my country, there are now periodical Covid-19 "info spots" interrupting the display of timetables, check-in desk and gate information screens.