Not a silly question. There were two types of calls that could be made during this time: person-to-person and station-to-station. If you had a specific person you wanted to talk to you would request a person-to-person call. You wouldn't be billed for the long distance charges until that person came to the phone. This was metered by having the operator on the line with you until the person you wanted came to the phone. Station-to-station calls were made when you didn't really care about who you talked to and one could leave a message with the person who answered if it was intended for a specific person.

Interestingly, person-to-person calls are still available though I don't think anyone uses them anymore. If you look at AT&T's rates for operator assisted calls it shows why one might have hesitated to use this service. The prices were much higher for person-to-person. The upside was you'd likely get billed for fewer minutes.

An interesting note about billing.. the way that billing worked back in the early days of cross country calling was that it was billed in three-minute increments. I have an advertisement from 1927 from a magazine (unfortunately I don't know what magazine as it was just the single page when it was given to me) that says that a call from San Francisco to New York was $9 per billing segment. If you take inflation into account that would be around $120 or $40 per minute today! Clearly you had to be very well to makes calls of this type for personal reasons.

Now regarding privacy, when working with the telegraph and telephone companies at the time there were often a number of people involved in the loop. With telegraphs there was someone on the sending and receiving end who were privy to your communications. With phone calls it was very easy for the operators along the route to listen in, though it wasn't really standard operating practice to do so. The employees of whatever company was employed were of course supposed to keep everything in confidence but you can imagine this wasn't always the case.

That's not to say that privacy wasn't a concern. There's a documented case of a tenant trying to break a lease when they discovered their calls were being listened to. A judge in the 10th District Municipal Court of New York City ruled that it was legal for the lease to be broken. (New York Times, Dec. 1, 1907, p. C12) Relatively early on there were concerns from the financial industry about telephone privacy as well. (See a letter published in the New York Times, Apr. 22, 1916, p. 10) It wasn't really until the advent of Direct Distance Dialing in the 1950s and 1960s that one could feel relatively secure in an operator not listening in on their calls.