Q: "These two workers are working on putting up some kind of metal building." Does this mean that "The workers are driving trucks."?
A: no

Q: "Two people riding dirt-bikes in a somewhat wooded area." Does this mean that "The people are shopping at the mall"?
A: no

Q: "Two people are kayaking across the water in front of a cloudy sky." Does this mean that "Two people are kayaking"?
A: it is not possible to tell

Q: "A marching band line stands and waits in full uniform." Does this mean that "A marching band waits to compete at a band competition."?
A:
it is not possible to tell