WGTdbloshoe: It left the moment Virgin America said they didn't have enough fuel on board to make it from Florida to SF and had to stop in Las Vegas
Hmmm, I think someone was telling you porkies. Unless something dramatic such as major deviation from planned flight paths and optimal altitudes or somebody screwed up flight planning, it would not be short of fuel as it would breach CAA regs. That said there is a well known US airline that used to fly into Hong Kong, and ask for priority landing due to low fuel (more than once) - was a croc, they just wanted have their R&R! Yes they finally got warned and never happened again.
And a 7 hour stopover in Vegas would lean to possible mechanical/electrical problems. Then add the Flight Time Limits and FDP (depending on crews origin point), you were lucky to get back the same day unless another crew was on standby (this could have been the reason for the delay).
So maybe you could not gambol but look on the bright side, you got home pretty much the same day.
Funny I flew Virgin Australia for the first time a few weeks ago, only complaint was cattle class is inhumane.