Q: "Two guitarists dressed in white perform." Does this mean that "Two people in white have guitars."?
A: yes

Q: "A person with gloves and a welding mask is welding metal in a factory." Does this mean that "A person is welding a mask."?
A: yes

Q: "An off road motorbike climbs a rocky hill." Does this mean that "The people are riding a bike"?
A: yes

Q: "A man in white playing Frisbee with some friends." Does this mean that "A man and his friends are throwing a green frisbee."?
A:
it is not possible to tell