Accoring to an article in 2003 this is what really happened
Popdirt gossip story from the even in 2003. They were re-running from the National Enquirer. As always, it is gossip so....
From January 2003:
Mariah Warns Christina About Battle With Booze
Mariah Carey has reached out to Christina Aguilera to urge the hard partying pop tart to seek help before she spirals into a full-blown alcohol and partying addiction. She told XXX-Tina, "You're going to end up burned out at 30, like I was!" The scene happened at the party Mariah tossed after the American Music Awards, where Aguilera got so plowed that she nearly lost her skimpy top. Mariah played big sister to the younger diva, begging her not to buckle under the pressures and temptations of young stardom that Mariah herself nearly flamed out on. Carey ordered her handlers to sneak the drunken Aguilera past photographers by covering her with a towel. Even while covered up, Christina continued boozing under the towel! But her cover was blown when her glass slipped and shattered on the sidewalk outside.