We frequently encounter bad experiences with GoToMeeting stemming from multiple users connecting in the same room and causing feedback loops.
This is a common scenario for us when multiple team members want to share content from their personal laptops, or when a new organizer comes in for a multi-part meeting and transitions the meeting to another computer.
I'm an IT support person so I understand the cause of this issue and how to mitigate it, but it's hard to communicate to users with the current UI. People think it's okay for another computer to join the meeting as long as it's "muted" in GoToMeeting, but in reality feedback can occur even when the mic is muted, because the speakers are still active.
Managing this is confusing to users and needlessly complicated because you need to monitor controls in two places (mute mic in GoToMeeting, mute speakers in Windows taskbar, which on Windows 10 may be hidden behind a submenu if the speakers are not your usual 'default' device), so in these scenarios we usually recommend users just choose 'Phone Call' and don't call in, to ensure no audio is connected. I think it would be much easier to manage this use-case if there was a third, "No audio" option, which effectively would do the same thing as what we recommend now. Ideally it could even have some helpful text underneath, like "choose this option if someone else in your meeting room is connected to audio".