There are 2 types of Emergency Locking Retractors on seat belts.
“Belt Sensitive” which locks up when you tug on it very quickly.
“Vehicle Sensitive” which relies on a sudden change in direction and cannot be tested with the rapid tug. It has a “universal inertia mechanism” device built into the retractor and will only lock up when there is a significant change in direction.
Many vehicle manufacturers place the Belt Sensitive system in front seats and the Vehicle Sensitive systems in the back seat for passenger comfort. If you are more confident in the vehicle system functionality, there is no harm in engaging the ALR when using the RideSafer by slowly pulling the seat belt all the way out. But in most cases we do not recommend it simply because when engaging the ALR mode on the retractor the seat belt tends to get tighter and tighter with each bump and corner, which could become uncomfortable for the child after a while.