Asking the ride operators upfront is just stupid. They are usually really busy trying to get everyone through as quickly as possible. You will most likely get a big NO for an answer. Its much smarter to contact park management or somebody of higher authority that a ride operator, as they will most likely give you a better answer. I have found that on slow days, really slow days, where there is almost nobody in the park, they sometimes let you bring it on. This is still rare to find.
Most POVs are completely unnecessary. This website has POVs for alot of roller coasters and if they dont, chances are somebody on youtube does. If they don't then even the park website does. If you are just doing it to get the thrill of breaking the rules, then do it elswhere, and places that will not harm people.