Slinky's right. Not only do streaming sites throw in the ads, but if they think the content may match some copyrighted content, their bots can just automatically shut it down and auto-ban you at any time. Just like they did this weekend with Worldcon and the Hugo Awards. They banned WORLDCON. In the middle of the HUGOS. Neil Gaiman was giving a speech accepting an award for Doctor Who when they banned the account for showing authorized clips of Doctor Who at the award show. *facepalm*

With those sites, the worst part would be not knowing if you were going to get through your event or not, knowing they may shut it down at any time. :(

At least with YouTube, we get things uploaded early enough that if we're going to get content match warnings, we know and can do something about it rather than just getting auto-banned outright while people are watching.