You have the obligation to be constantly looking for better opportunities. No decent person would ever begrudge you that.
Nobody hires you expecting you to leave right away. They invest the training in you expecting you to stay long enough to get a return on that investment.
Also I hope you guys realize it is not always easy for somebody completely overqualified to get these poor paying jobs. If you apply for a job making drastically less than you used to they assume you'll be looking for a higher paying job and not hire you. They don't want to invest in training just to have you leave right away.
Not skullpilot, He has many many employees and he don't mind hiring a few part timers that he enjoys training so they can leave and he can start over trying to find another low wage employee working two or three low wage jobs.
Right skull? No waste in hiring a part timer just to see them leave in a couple months. I am surprised that every employer doesn't require their part time people to have more than one part time job.