Not necessarily. In what version of English do you write? The tendency to add the comma before the word ‘and’ is, as far as I recall, an Americanism; in English English you wouldn’t have the last comma the ‘and’ makes it redundant.
In proper English grammar there is a comma.
`Joe, Bill, and Phil went to the store.`
No not necessarily – he said once again 
Look it up or am I being rude and in fact you’re an English teacher in which case I’ll shut up 
I don’t think it should have a second comma in the UK….
Look it up or am I being rude and in fact you’re an English teacher in which case I’ll shut up
???
http://grammar.ccc.commnet.edu/grammar/commas.htm
If you lot want to argue spelling, or grammar, or punctuation, do it on your own blogs or another discussion forum. Not here.
My only comment will be that I do not view this as an error. This may be a British/American English thing, but I’m certainly not well-informed enough.
I’m not arguing. I’m just saying you have a grammatical error, but obviously you don’t want to fix it.
Closing topic. This is not the place to argue about grammatical syntax in English language.
@DJPaul spoilsport :p
@vegasparty607 erm yes and that link is to an American educational resource! try looking up a general one and you will find that there are exceptions and differences to the use or not of a comma and ‘and’ 