That is why you need at least two, sometimes three judges to measure the time of the race to the standard needed to enter the record books.
It would make no difference how accurate or high-tech the wristwatch was.
But they omit discussion of the basic flaw in the method: you cannot measure the age of a rock using radioactive dating because you were not present to measure the radioactive elements when the rock formed and you did not monitor the way those elements changed over its entire geological history.
If you check this educational page by the US Geological Society you will see that they spend all their time talking about the technicalities of radioactive decay.
Metamorphic rocks are not always easy to date using radio-isotopes.
Results obtained usually signify the "date" of the metamorphism, but they may also yield the "age" of the original volcanic (or sedimentary) rock.
We note that at the instant the swimmer touches the edge of the pool our wristwatch reads and 53 seconds.
How long has the competitor taken to swim the 1,500 metre race?
During the race you have to watch the swimmer and count how many laps he has swum so you know that he has done 1,500 metres.
And you have to check to make sure he touches the edge at the end of each lap.
Without these observations you cannot be sure that the time is valid.
A swimming race illustrates the simple principles involved in measuring time.
This swimmer is competing in a 1,500 metre race and we have an accurate, calibrated wristwatch.
It is also claimed that the original basalt lavas were erupted between 17 Ma, based on U-Pb dating of "original" zircon grains in metamorphosed felsic (granitic) volcanic layers within the Brahma and Rama Schists.