Most jacks have such small wheels they have a hard time rolling to compensate for the radius change as the pad lifts. Only the big professional-type jacks have much chance of the rollers moving as the lift is made. The tiny wheels on the hobby jacks are just about worthless. Once the jack stands are in place, chocks or setting a park brake might be a good idea.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!