Jetpack does it again..
“The following new modules have been activated..”

This is might be a good thing for some users, perhaps even the majority of Jetpack users, and judging by Samuel's explanation above it certainly sounds like a clever approach to the problem. But personally I'd appreciate if a plugin asked me before changing the settings on my site.

At the very least check if there is another Brute Force Protect plugin around, which there are in many cases.