One of my users let the cat out of the bag and told me they were using one of my free apps, which is monetized by ads, but they were blocking the ads with an ad blocker. The
There is nothing you can do that your users can't do better.
The only thing that comes to mind as remotely effective is to make the ads an inextricable part of the program, so that if they're blocked the user cannot make sense of/interact with the application.