We've upgraded to Proclaim 2.0, and got two interruptions during the service.
The first happened because Proclaim lost focus, so our wireless presenter stopped working. We fixed it by clicking back on the next slide in Preview. I think the cause of losing focus was a Proclaim message that popped up during the presentation (the one that comes in the bottom right hand corner, announcing new features or the Monday minute, etc.). Certainly a message appeared at that time that wasn't there shortly before.
The second time, Proclaim tried to install an update midway through the presentation. The UAC screen came up, and all connected screens went blank. We knew there was an update pending when we started Proclaim, and started to download it, but there wasn't time to install it before going live. We therefore cancelled the update. Then we restarted Proclaim and skipped the update. It was about an hour later (or more) that the update then tried to install itself and blanked all our screens.