Everybody is entitled to use whatever equipment in the gym. That is why everybody pays dues to work out there.
There are hundreds of members and only so many pieces of equipment.
Working in lets everybody, you included, get in a workout.
Now, am I going to work in on the leg press with a girl who weighs 95 pounds and uses one 45 pound plate loaded on each side of the leg press. No! But if you are a dude, yes.
And I tell every single person who asks how many sets I have - well, I tell them, but then I invite them to work in. If I find out later they were waiting and did not ask, I go out of my way to tell them, "In the future, come work in. You are always welcome. Just come work in."
Ought to be normal gym etiquette everywhere.