I’ve streamed over 150 live streams on YouTube, most of them longer than 2 hours. I mostly play music from the 90s but I also play new and very commercial music, but I’ve yet to experience a single case where the stream has stopped mid-set.
I’m located in Finland (if location has any affect) and I do get the copyright emails ( FAQ: Why do I get copyright emails from YouTube? ) after the set ends if I forget to delete the video. I can get anywhere from 0 to 100 copyright emails, depending on the tracks and their count. And like explained in the linked topic, the emails are pointless and don’t affect anything.