When is it appropriate to address someone as 老板 [laoban]? I've heard laoban being used multiple times when addressing shopkeepers. But who exactly do you refer as laoban?

For example, I suppose it's safe to address your boss as laoban regardless of where you work, but if you're a costumer should laoban be used only for the boss/owner, or can one safely refer to any employee like that?

In a school setting, for example, if the director is the owner can you call them laoban? What if it's the receptionist and you don't know who the boss/owner is? What if you work at that place?

As far as ways of addressing go, are there more than one laoban in a given shop?

In these scenarios, what would be some other forms of addressing if there are better ones?
Laoban is often used in daily speaking language. 

People working in shop or restaurant often use this to address their customer to show some "respect" or to make you feel good. Like in the car washing shop, they often call you "Boss".

The beginning uses the word was from late 80's, start from the south part of China, maybe GuangDong. 

If you are working in a high-tech or similar place normally don't directly use this word to call your boss. But it's absolute normal use it when chatting with your colleague. 

For University, graduate school students often use laoban to address their director teacher. 

Normally in daily life, you can use laoban to call anyone is in the manager place. Like you can call your partner laoban.