When did it become OK to not wear pants?

While we've grown increasingly fascinated/freaked out by singer Lady Gaga's monochromatic space outfits, we're even more disturbed by the fact that similar garments, or lack thereof, are making the rounds in the entertainment biz.

Beyonce wore a leotard and heels in her infamous "Single Ladies" music video, and Ciara recently followed suit in her latest video. But now Victoria "Posh Spice" Beckham showed up on the red carpet without pants too! We get it, ladies, you have great legs, but have you forgotten that you're supposed to wear something on your lower half when leaving the house?

What do you think of the no pants movement? Can famous people get away with wearing costume-like attire, or should these ladies cover up?