That kid (teenager, whatever) shouldn't have been allowed to enter in the first place... with those kinds of contests, don't you have to be 18+ (or whatever the legal age is. I think in GB, it's 18.) to participate?
I hardly blame this on Coca-Cola completely. The kid signed up for it, and she should have expected that pretty much anything goes, and that was the point of the "status takeover." I do think that they should have only allowed (if it wasn't the case) 18+ year olds to participate, and should have had a disclaimer that the statuses may not be the most kosher ever.
The mom has every reason to be upset, but she should be more upset with her daughter for either lying about her age or not reading the fine print than with Coca-Cola.
Just an opposing viewpoint.