Make It a Trenta

I was caught off guard on my afternoon Starbucks run when the person behind me ordered a Trenta. In case you haven’t heard, a Trenta is the largest addition to the Starbucks line: it holds no less than 31 ounces of coffee.

I’m not looking to rant about consumerism or nutrition or obesity or even supersizing, but “Make it a Trenta”?! Doesn’t that sound like something out of Star Trek?
I’m trying to imagine saying “…and make it a Trenta”. But as I visualize holding a cup that is larger than a reasonable purse and only a fraction smaller than my everyday handbag, I feel like I’d need to wear a sign justifying my 31 ounce decision. Perhaps it would read “I just took the red-eye home” or “All day meetings” or “Exams”.
And wouldn’t that much coffee or tea necessitate equal parts water to prevent dehydration? I wouldn’t want to go on a day long road trip with someone drinking equal parts water and Trenta (as a note: hours of driving would be another sign-approved reason for purchasing a Trenta, though I’m not sure it would be the wisest choice).
Who knows maybe six months or even six weeks from now 'everyone will be doing it'. All I know is, on my next trip to grab a latte, I do not intend to make it a Trenta.