I'd consider it rude to sign anyone up for anything without knowing for a fact that they'd appreciate it. Especially if it's something that costs money to sign up for, you'd feel obligated to go. It doesn't exactly eat up your whole day, but when you're on vacation in another state you might have back to back plans of things you want to do/see. That said, the boyfriend could have given her a heads up but he may want a fit girlfriend and his parents have taken it upon themselves to do this little test just to see her reaction, let alone how well she does. The fact that she didn't even go and just enjoy being outdoors while being near them and still on reddit or whatever shows that she flat out refused their company along wasting whatever money they put down to register her for a 10k.