I would hope if he was offered the opportunity he chose to turn it down because he knows that an edited for television reality show can be made to make a person or business look anyway the editors want it to look. Most episodes of Undercover Boss I have seen follow the same script. The CEO is made to look like a buffoon both with a ridiculous disguise and by the show pointing out that the CEO can't run some piece of equipment. The company then gets slammed over it's policies and procedures by some employees and the company is made to look like it is run by a bunch of monkeys. Then those employees get a reward for doing their job. And that is the last we see or hear about it. A responsible CEO does not turn his company's reputation over to reality TV.
And Mr. Lemonis has had a little experience with how a potential good deed can turn into a nightmare. Do a little research on his restaurant rescue/investment. I quit following it, but it was turning into a nest of snakes the last time I saw anything about it. Both sides were accusing the other of basically being satan in the flesh. Way too much downside as far as I am concerned.