This is more common than just black widows...

Sadly many people don't do any homework on the tattoo "artist" they choose and many times money outweighs artistic merit.

I grew up playing with black widows. They were EVERYWHERE around the property, hiding in all the dark spots. You get used to them and I have never been bitten by one. This after spending years actually poking at them and playing with them. The true look of the black widow is solid black. You only see the red marking when the spider is upside down in its web. At least the west coast ones.