Most likely this is a kind man trying to do something nice for some kids. But if that is indeed the case, he would be wise to at least include his name and phone number with the cake to assuage any concern a parent would naturally have in these days when it is only prudent to have concerns. The parent could call to make sure the name and number are not false, then know where to send the police if anything turns out to be amiss. Better still, ask the kids if they would introduce him to their mom so he can present the cake to her if she wants to accept it.