Maybe one or two times in the 10 years I've had Dish. The problem with those channels is ESPN can use them but Dish usually doesn't update the guide (quick enough). I want to say I watched a football game, don't remember if it was college or pro, that ended up on one of those channels and only found it by chance. They could be used other times but I'm not necessarily looking for anything on those channels.
When I had ESPN, it made sense that those show in the guide though. With the base Flex package, as you know, it includes no ESPN, so there's no need to show the ESPN alternate channels.
I just want Dish to know about this. If they fix it, they fix it, if they don't, they don't. I'll probably block them on my own. I'm like you - I block a LOT of channels.