It reminds me a little of the way in which airbags are always described as "SRS" (for "Supplementary Restraint System"), to try and make it clear that they're s

It reminds me a little of the way in which airbags are always described as "SRS" (for "Supplementary Restraint System"), to try and make it clear that they're supposed to be used with seatbelts, not instead of them.