Imagine two similar scenarios.
You are walking past a house in a typical neighborhood. You happen to notice through a window that has its shades/curtains open that people are engaged in the throws of passionate love making. Whatever that looks like for you is fine (gay, straight, kinky, vanilla, whatever). You are intrigued and so you stop and peer in through the window. The actors in this situation have no idea they are being watched. Basically run-of-the-mill voyeurism.
Second scenario is basically the same but this time you can’t see anything. The curtains and shades are drawn closed but the window is open so you cannot see anything but can hear everything. You stop and listen instead of peering in. The actors do not realize they can be heard.
Assume in both cases that nobody knows you are a witness to these events and the people involved do not know that their actions are being witnessed in any way.
How do these situations feel to you. Are they different? Is one more ok or less offensive than the other?
Why?