I think all of the versions I have posted so far will slowly flash the battery icon with a red outline (5 sec red outline, 5 sec normal, ...) , so it draws some attention without inteferring a lot in what you are trying to do. A beep and/or pop-up warning might be nice, but for now, I think I'd like to freeze the features as-is, fix any significant bugs, and call it version 1.0.0. For the versions leading up to 2.0, we can experiment with some different alert features. Maybe some new applets too.
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Mike L.