It ain't silliness. The spider (I think) that SRS speaks of are in California--members of the tarantula family called Black Mountain Spiders by the local folks in the Sierras. Had two as pets many years ago. Looked like this--but I suspect this one is quite young.

I'd built them an 7' x 3' x 2' screened cage. Fed them grasshoppers and other bugs. They could turn a 3" grasshopper into a cubic cm of leftover and they were very fast. I couldn't have clicked a stop watch fast enough to time a 6' run. But generally they just lazed around. Never found them to be aggressive with me, but I never got between them and their food.