Personally I rarely hang around a place after I've gotten the payment or cargo. Usually part of the fun is getting away with the loot. But I agree with Doria I think if they do hang around and insult you afterwards they passed up the option to pass by safely, seems like a new interaction. Especially if you keep it in roleplay the whole time it seems reasonable a guy with a gun my use it regardless if you irritate him. Its true that traders are likely willing to do so not because inrp it makes sense to get brave after paying a pirate, but because they believe they are exempt from destruction after paying the initial demand.