There’s a trend toward open punctuation, which means using fewer commas. For example, short introductory phrases usually read fine without a comma.
At noon let’s eat.
I recently became aware that I was using commas to set off too, and I couldn’t cite a rule for doing so. It was simply a (bad?) habit I acquired from grade school.
I must have my cake and eat it, too.
I consulted an authority: The Chicago Manual of Style Online. Turns out there’s no reason to use commas with too. Commas are used only to show an abrupt change of thought. Chicago offers this example:
He didn’t know at first what hit him, but then, too, he hadn’t ever walked in a field strewn with garden rakes.
Is that a seasonally appropriate sentence or what?
Still, I don’t plan on using too in this way very often. So as a proponent of the judicious use of open punctuation, I’m only too happy to jettison the comma.