Evidence in favor of using a comma before the 'and' in a series

Yep. The comma would've made a huge difference.

:D

:)

:rofl:

:rofl:

One reason why is scope. Consider the set {a, B, C}.

This can be written:
lowercase a, uppercase b, and uppercase C
or
lowercase a, uppercase b and c.

But the form "lowercase a, uppercase b, and c" would be less clear. And while the first form is most precise, in writing avoiding the wrong sort of repetition and the use of ponderous forms is often desirable. So, for example, the first form might be used first in the text in order to be most precise, and then the second form used thereafter as a "cleaner shorthand".

Another reason is transition. Considering the same set again, if this list is followed by a semicolon, then the transition is blunt:
a, B, and C;

But depending on what surrounds, a comma might seem a weaker, less "eye-grabbing" transition:
a, B, and C,
a, B and C,

Now, these are oversimplifications, and context is generally essential to interpreting writing. But giving your reader little aids can be helpful.

(Not that I really follow any set of rules; pretty-much I just go with what seems to read well, what seems to work.)

It can be difficult to "step back" from your writing and see what you actually wrote (how this text might be variously interpreted) -- as opposed to what you intended to write.

This is one reason I like to give several "wakeups" (the new perspectives that breaks in the stream-of-consciousness can bring) to anything of significance (of course, by then it might be untimely; so I often write things in advance, look for some opportunity to use them -- and then modify to suit). But there's nothing quite as good as having some (useful, helpful, willing) peer to review what you write.

The order was out of order.

Among those interviewed were Kris Kristofferson, Robert Duvall and the singer's two ex-wives.

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"With gratitude to my parents, Mother Teresa and the pope."

http://thelaughorist.blogspot.com/2009/05/serial-comma-wars-continued.html