In theory, yes. In practice, they haven’t been for a long time.

I remember speaking with a scheduler a few years ago about an unrelated issue — as multiple IAs were going out. After taking care of the issue, she asked me if I was interested in any of the IAs. I said “No thanks”. She said “Have a nice day” and hung up. Schedulers won’t try to compel you to fly IAs here as they do at other airlines.

(Of course, even if she wanted to force an IA on me, I was out of position and had just cracked open a beer.)