"I wonder what would happen if ... you delete the event."
Busy Me checks if an event is occurring at the "current" time--essentially ignoring start and end times. If you delete an event from your phone's Calendar app during the event, your phone will be restored your ringer at the next 5 minute check (unless your settings say to never turn the ringer back on). If you delete from the calendar.google.com
website, there could be a delay in that being synced to your phone's calendar."...include other actions based on different keywords, like wifi state, gps, flight mode, etc."
While I plan to do things like auto-reply to calls and texts, prompt to return ringer to normal after a set time when you manually turn your ringer off, etc, I don't intend to make Busy Me a full settings manager. There are apps of apps like Locale and Tasker that already do a good job at that."...allowing keywords to occur in the description rather than just the event title."
You can add already add #busy
into the description field, but I can see how this might be useful. Descriptions can be bloated with all kinds of text, so I thought it would be overkill. However, I'll look into it for a future update.