Eliezer Gersten asks:
Is there some logical explanation why the owner being with the barrower should exempt him from paying or is it just a Gezeiras ha'Kasuv?
Eliezer Gersten, Israel
The Kollel replies:
The Sefer ha'Chinuch, in Mitzvah 60, attributes the Din to the fact that the owner is with the Shomer at the time that he receives the article, and thus we may assume that he takes responsibility for it and does not expect the Shomer to do so. See inside how he elaborates on that.
See also Torah Temimah, Shemos 22:13 (note 153), who queries the Sefer ha'Chinuch and offers other explanations.
B'Virchas Kol Tuv,
Eliezer Chrysler