Can a business legally place a video camera that records conversations in their store without placing proper notification on the wall?

Recording laws differ from state to state which, I hope, accounts for the answers you have received. Recording video of customers and employees for security purposes on company property is almost definitely legal. However, in California, state law requires that all participants of a conversation be aware that they are being recorded. By recording conversations, without verbally advising his employees or customers that he is doing so, your employer is violating California Penal Code Section 630-638.

Yes, they can. No need to ask for an employee's permission, since they don't own the place. "Own" being the keyword here. The owner/employer has every right to protect their business in any manner they see fit.

They don't have to get customer permission, either. As a customer, I would expect it - you would be a moron not to in this day and age of cameras.

You don't have to like it. You have the option of quitting.

in general, yes. the specific cases where it would be illegal would be when the camera is set up to create or record events for sexual exploitation

So let me get this straight. You are trying to get YOUR boss, the one who pays you and puts money on your plate, into legal trouble? Over something that doesn't even really concern you? You traitorous backstabbing little snot! You should be fired!

Yes. If you are so stupid to not notice the camera, then what does that say about you

Of course. They can hide them, etc, all they want. No need to disclose at all.