User blog comment:Darkcloud1111/''The Mark of Athena'' Plot Holes/@comment-4515675-20121021160447/@comment-175.144.174.179-20130425142937

well, for the cell phone issue, Annabeth does have a cellphone, even thought she's not supposed to. And Percy also mentioned in one of the books in PJO, that several other demigods secretly have cellphones. So i guess, Leo is one of those rare, rule-breaking demigod. and as you know, he IS a bit cocky about his ability outside of i'm-about-to-die situations. So he probably thought that he'll be fine having a cellphone...