-1 cannot reproduce (possessing a gmail account without dots, I cannot create a similarly-named gmail account with dots in).
Once someone has created j.smith@gmail, jsmith@gmail can no longer be created -- because they are the same account. It's not possible for you to have j.smith@gmail and someone else to have jsmith@gmail.
I get other peoples' mail all the time. It's not because gmail is misdelivering mail with dots in account names. It's because someone has another letter in their account that somebody left out (jjsmith, jpsmith, jsmith1, etc.) It's the sender, not gmail, who is directing the mail to the wrong inbox.
If that is not what you mean, you should edit it to make it clearer.