My suggestion I give to first timers is to always speak . Just say no thanks or not interested . Don't ignore and keep walking and don't say I'll shop with you later cause that will remember you said that. I actually enjoy the haggling but I realizE some people are shy and have a hard time with it.
Now regarding the cruise that's a different story. I cruised once to Falmouth and actually had some Negril friends pick us up.
I could see there was a whole different level of intensity there as the salespeople know it's a one time shot. If that stay in Falmouth had been my first time to Jamaica I doubt I would have ever gone back