This is just a suggestion for consideration.
Under the Alerts section, specifically the Alert me when someone with administrator access signs in/Alert me when a non-admin user signs in, I think it might be useful to have the ability to prevent alerts from being sent if the log in comes from a specific IP (or range/list of IPs)
For example, if someone always logs into their site from the same IP (in their office, home, wherever), they may not want to always get an alert indicating that they logged in - they already know that.
What they would be interested in is being alerted if someone signs in from another IP - likely a bigger indicator of someone gaining unauthorized access. Yes, this could throw up false flags if the authorized user is in another location, but that might not be a frequent scenario, so it wouldn't overwhelm an inbox with unnecessary alerts.
This type of alert could be an option, so that someone could still get alerted for all sign-ins if they want. For example, check the box to be alerted for admin/non-admin sign-ins, and if an IP, or list of IPs are entered filter the alerts so they aren't sent if signing in from those IPs. If no IPs are set, then send the alert for all sign-ins.
I only bring this up because I can see some people, who get the alerts for all sign-ins, becoming "numb" to an email every time they sign-in. They may see the alert and teach themselves to ignore it as it usually contains information that they already know (that they logged in).