It has been all over the news here. A workman found some black widow spiders in some construction equipment last week.
I have several around the outside of my house as I sit here and type. Many crickets and roaches in Arizona, especially on the outskirts of developed areas, like where I live. BW spiders help control these other pests and since BW's are orb weavers, they never leave their nest, ergo you always know where they are.
Scorpions however are another matter. We have them here and they are roaming hunters who can squeeze themselves very flat to fit in the tightest of cracks. They are also highly resistant to insecticides. One species here in AZ, (bark scorpion) is deadly to small children, the sick and the infirm. They are small and almost clear so they can be very hard to see.
Saw a rather large scorpion in one of my garages the other day, not 3 feet from my open hockey bag. wonderful.......