All I can state is that it didn't automatically trigger a forfeiture in my case. All I did was book and cancel award rooms a few times without any other qualifying activity until several months after my points were supposed to expire, even when the new bookings were made past that original expiration date. So (at least at the time of my experience) it seems like the system only cares if there was some type of "qualifying activity" within the last 24 months.