^^^ Most employees are not high profile people and their employers would likely not know of any possible legal troubles unless they were sent to jail.
Really.
I had a friend who got into some trouble with her employer when she was charged with a "crime" that is not even a misdemeanor but a violation with a maximum sentence of a $50 fine. The city didn't even prosecute her "crime."
Details:
Her job: second grade teacher.
Her alleged crime: public urination, 2 am behind a bar during school vacation week in another state. This particular city didn't prosecute first offenders but would publish their names in the local paper and send the names to the perpetrators hometown paper when they got arrested.
While she didn't get fired or suspended she did get a letter of reprimand and a warning that as a role model for the students that any additional type problems might result in her not getting tenure.
She is neither high profile nor did she go to jail.
I disagree with your premise that most employer would not know of the legal troubles of an employee. Almost every city has a "police blotter" section in arrests are listed. Odds are someone is going to read that and bring it to the bosses attention. In fact that is how we often find out about the legal trouble of high profile people.