To get out of the county right before you get arrested and/or whacked.
Named after Robert Vesco an infamous criminal financier in the early 1970s who, before the FBI filed charges, took off to the Caribbean with hundreds of millions of dollars.
"If he'd waited another day to vesco the hell out of there, he might now be lying dead at the hands of some vengeful S & R rover." - Dean Ing's Single Combat (1983)