Who knew that anyone was going to take "Pants Off, Dance Off" so seriously, much less every pop star under 50! Going pantsless has become a pop trend we just can't deny. No one who is anyone wears pants anymore. Take Sunday night's American Music Awards for example. Carrie Underwood performed in booty shorts, Jennifer Lopez in some silky skivvies and Lady Gaga in what we think may have been nude Spanx. Where have all the trousers gone? Our experts weigh in after the jump.