The previous owner replaced all the windows in the house (I'm guessing) around 5-10 years ago with vinyl double-hungs. There are ventilation latches/locks that can prevent the windows from being opened more than 4 inches. (They are actually part of the window. Little triangle things that pop out.) It was explained to me during our initial home inspection that it was added home security.
Recently, a window company told me they absolutely are not designed for added home security. Twenty pounds of pressure will break the ventilation latches. The ventilation latches are to prevent children from opening and falling through a window. He said that all of these latches (no matter who mine were purchased through) are manufactured from the same company so there is no such thing as ones designed for general security.
My BFF just bought windows for her house and the company marketed these latches as home security. The guy actually had a sample window, stepped on the edge, and jumped on it to show that the ventilation locks wouldn't break.
I'm trying to find out my manufacturer (I've taken the whole window apart and cannot find it anywhere google tells me to look.) But I'm curious if anyone else has come across either explanation from their window company?