Even in an At Will state, there may be some gray areas. e.g. if in reliance on an offer, you have given notice at your previous job, sold your house and relocat

Even in an At Will state, there may be some gray areas. e.g. if in reliance on an offer, you have given notice at your previous job, sold your house and relocated across several time zones, only to be immediately laid off, you may have a legal claim against your employer. Disclaimer: Not a lawyer, and haven't experienced this scenario myself.