I agree with Marc and Fred.
You should be accepting the park's rules. If the park tells the employees not to let people do it, they're just doing their job.
Besides if they let one group of people ride again, the people entering the station from the queue will want the same thing afterwards. If you do it for some guests, it's rude to other people in some cases.
And trust me, I work in a place with lot's of customers, and it's s**t when people shout at you for something you don't decide.
I know it's a bit of effort, but is it really that hard just to walk out and enter the (supposedly empty) queue again? If it's empty enough for you to "demand" a second ride, then you won't be waiting in the queue to ride again.