Not! I currently work for 3 PDN companies and have been since 2012. I've probably refused 15 cases in that time. It's absolutely acceptable in PDN. Dude was just trying to intimidate you since you're new. It's been tried on me and in the beginning it felt terrible. But now after years of experience, I immediately check that if a new scheduler tries that mess. I've even been interrogated by the CM (clinical manager) as to why I chose not to take a case. I just stood my ground and said it's not for me. Usually I explain my reasons though. That was just a personal thing. The whole concept of PDN and the meet and greet is that you're BOTH happy with the assignment. If you have it in you, I'd report that scheduler. That's unacceptable. Every company is begging for nurses to be able to fill shifts, getting complaints from families about unfilled shifts. They need you. If you realize this fron the beginning, you'll understand your leveraging power. And they WILL pay you extra to take certain shifts. They just don't want that to become common knowledge so they'll tell you to not discuss your payrate with fellow nurses.
I could go on... but just know, you are extremely valuable to the company. DON'T let a putz scheduler pressure you bc he's stressed that he's responsible to fill an open shift! Be flexible, take shifts and help out with coverage when you can, but saying no to a case is your right in PDN. Once I even told a scheduler, "Hey, there's gotta be some benefits (being able to refuse a shift) since the pay is such crap". She laughed and agreed.