Yeah, I've had people quit without notice.

I'm just like "Okay, that didn't work out. Moving on ..."

If someone doesn't want to work for me then it's better for both of us to just move on.

Only once did another business call me about a former employee that I had a negative experience with. Said employee was fired for theft.

No idea why they listed us as a reference or how the new employer found out about the work history, but I just confirmed "Yes, XYZ worked for us."

AFAIK as an employer I can actually risk trouble if I say too much about a former employee, so I just follow the "If you don't have anything good to say, don't say anything" rule.

The other employers get it. "No comment" means "don't hire". No specifics necessary...

No good business is petty enough to bother with such nonsense.

I'm sure some businesses are petty enough to go out of their way to harass former employees, but workers should endeavor to refrain from applying to said businesses whenever possible.

(Easier said than done, I know)

Sucks that you can't always tell at first if it's a shifty business or not when applying.