Who was the man with the clipboard and pencil in "Raymond's Run"?

In Raymond's Run, the man with the clipboard and pencils is Mr. Pearson. Mr. Pearson is the one in charge of pinning the numbers on the backs of student runners.
Before the race begins, Mr. Pearson approaches Squeaky with his clipboard, cards, pencils, whistles, safety pins, and other paraphernalia. The narrator, Squeaky, is upset that Mr. Pearson uses her nickname to address her. She tells him to call her "Hazel Elizabeth Deborah Parker" instead.
Squeaky tells us that the children used to call Mr. Pearson Jack and the Beanstalk. This is because he walks on stilts. Mr. Pearson does not like the nickname and often gets angry when he hears it. However, Squeaky maintains that she is beyond all that "silliness" now and no longer participates in antagonizing Mr. Pearson.
For his part, Mr. Pearson hands Squeaky her number and divulges that there are only six girls running. He tells Squeaky that the new girl Gretchen should give her a run for her money. Then, he tries to suggest that Squeaky extend a friendly gesture to Gretchen. This prompts Squeaky to walk off in a huff.