What if someone (Google) used Google suite to send 10k emails to fire people. Wouldn’t that be considered normal for the server for a day let alone a week. Yes I know I could have come up with a better example.
The example was given to say you could be a gsuite customer and have 10k emails a week be very normal. Something that wouldn’t trigger any alarms unless set. The alarms would probably be set on a curve. Something unusual would be far off the curve.