city worker

Yes, of course they may do it. And they are right to do it. Their task to check if your restaurant (and the others)keep the rules, you must keep. If they let you know in advance, then you would hide that you did not want them to see.

In most states a city code inforcement officer or inspector, as you put it, will only come to your home if someone has made a complaint or if your property visibly does not meet city ordinances in one aspect or the other. For instance, if you have several junk vehicles or an excess amount of accumulated items lying around in your front yard. The officer is not allowed to physically go 'on' your property (unless he is knocking on your door). He is not allowed to 'peek' over a fence that is taller than he is. He is allowed to take pictures (as evidence of a code violation) if he can visibly see the problem. I would suggest you go online or visit your City Hall for a copy of Code of Ordinances for your city. You might find them very interesting.

I believe they can, depending on what type of inspection they are conducting; If the dwelling is occupied, they cannot enter your house or yard without your permission (or permission of the person living there, if it is rented). They can usually only inspect what is visible from the street or from property they have permission to be on (like if they asked your neighbor if they could go in his backyard in order to look into yours). Hope this helps.