Fear of getting a ticket generally isn't what controls that.
I slow down immediately when I see someone signal who wants to pull in front of me in my lane.
If I notice someone frantically changing lanes to get ahead a few spots, I'll begin to make room for that person as soon as I can if it looks like I can help. If a guy wants to drive that way, I'll do what I can to accommodate.
I don't think I'd get a ticket for being a discourteous driver, but I prefer to have happy drivers around me than unhappy drivers so I do what I can to create the situation I want.