Does s2Member track visitor IPs?

Tracking Users by Their IP Address (Location)

As with any membership system, it is possible for one member to signup, and then share their username with someone else; or even post it online for the whole world to see. This is known as link sharing (aka: username sharing). It is not likely that you'll be attacked in this way, but it's still a good idea to protect your system; just in case somebody tries this.

s2Member's Unique IP Restrictions work for Membership Level Access (account logins), Specific Post/Page Access, Registration Links, and other secure entry points. In all cases, the rules are simple. A single username, access link, and/or entry point; is only valid for a certain number of unique IP addresses. Once that limit is reached, s2Member assumes there has been a security breach. At that time, s2Member will place a temporary ban (preventing access) to a specific post/page, or to an account associated with a particular username. This temporary ban, will only affect the offending link and/or username associated with the security breach. You can fine-tune this behavior through configurable options.