When numbers aren't numbers

Today, on #rubyonrails, a stubborn developer insisted on storing phone numbers as integers. The rest of the channel tried to persuade him/her that this was a really, really bad idea. Part of the conversation went:

<Cyanshade> you assume that all phones are in the US?
<stubborn_dev_02> yes
<Cyanshade> my phone number is in the form +358 44 123 4567
<stubborn_dev_02> then i’d ban you

(Name has been changed to protect the innocent)