They used to just remove the belt for engine drag?

Once you pull out the compressor it's a lot of work to put back in and get working again. Nobody is going to do that very often. Once she's gone that far I bet there are a bunch of other mods on that car.

Around here once you get that serious it's more common to buy a beat-up clunker with an AC you can use to tow a trailer so that the racer can be a Trailer Queen and not necessarily usable on the daily commute. That's especially true of the Toyota Supras modified to 700+ hp: it ain't gonna live long, so don't run in going to and from the track, much less work.