I usually take fullface and openface and spend most of the day in the open face. I’ll sometimes switch if I’m planning on doing bigger stuff but I’d not worry about it at all personally. And on a first visit you’re probably going to be spending a lot of the day just figuring it out rather than smashing out top speed laps and pushing it.
(I’m making a slight assumption here but I think it’s probably true… Most people will basically just go and ride like they normally ride. So if you already feel like maybe your riding could do with a full face, it’ll maybe amplify that. But if you don’t normally feel that way, probably a day at BPW will be no different. Or, put it a different way, I reckon that most people who should definitely take a full face if they go to BPW, already have one or at least want one)
You do tend to do more riding than you’re used to, and maybe get more tired or careless or carried away, and the downside of fullface is way smaller than in a normal riding day so those are good reasons to wear a full face if you have it but it’s not- imo- a reason to feel like you need it. At the end of the day unless you’re hitting the bigger features it’s just a trail centre with a bus.
I think overall what I’d say is go, have fun, if you’re feeling like you wish you had a full face then see if there’s one you like in the shop but just don’t get hung up on it.